# Yet Another Model 3 Wheel Thread



## Steven

Ahh wheels. I'm not sure what I'll do there. There's not enough difference in appearance between 18's and 19's in my opinion. Depending on if the width is also upped (we don't know that yet, do we?) then stability and braking performance can be enhanced, but at the cost of acceleration (noticable? Probably not), comfort, and range... not to mention $$$.

I'm sure people have gone over this exhaustively, but I haven't followed. Doing a Google image search I see a Model 3 in real life (r/c) having 235/40 R19's. I'm surprised they're that narrow for a 19. Going over to tiresize.com it looks like we *can* fit anywhere from a 225/70 R14 all the way up to a 325/25 R20 without affecting speedo/sensors at all (ie. identical outer diameter). Taking a 1.5% sensor hit (which may not be wise on a car so reliant on sensors!) we can eek out a 295/25 R21.

Interesting is that the equiv size 18's are 305/35 R18... considerably wider than the 19's. I'm guessing they'd go with the 235/45 R18 instead, which is 0.4% out and probably acceptable (an even narrower 215/50R18 is also 0.4% out the other way. That would maximize range). Of course, I'm basing this all on the 235/40 R19's being "correct", which is flawed logic, I know. Has anyone confirmed yet what is real?

I'd be curious about going to 14s  Mushy ride (good and bad thing depending on the quality of roads you drive) and... well, the look would be interesting lol And range would be improved, slightly anyway (unless the 18's are 215's).


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## ModFather

Steven said:


> Ahh wheels. I'm not sure what I'll do there.


Steven, now that we have talked you back from the ledge, I am happy to see your rehabilitation is going so well now that you are talking about important stuff like wheels! This is the fun part about dreaming and planning for the day YOUR car arrives and you behold for the first time with eyes and mouth agape and the bully Bummer boys will have their noses pressed against the Tesla showroom windows with their Groucho glasses on! Go to the "tire diameter" thread to catch up on some of the stuff you have questions about. @Mad Hungarian is extremely knowledgeable but surprisingly a really nice guy for a Hungarian, and always willing to help.

Remember, rehabilitation is a 12 step program and you just have to make it one hour at a time.


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## Steven

I'm sure that thread is somewhere. I have a hard time finding things on this forum. It isn't the greatest layout, at least with my phone.


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## Daliman

ModFather said:


> Steven, now that we have talked you back from the ledge, I am happy to see your rehabilitation is going so well now that you are talking about important stuff like wheels! This is the fun part about dreaming and planning for the day YOUR car arrives and you behold for the first time with eyes and mouth agape and the bully Bummer boys will have their noses pressed against the Tesla showroom windows with their Groucho glasses on! Go to the "tire diameter" thread to catch up on some of the stuff you have questions about. @Mad Hungarian is extremely knowledgeable but surprisingly a really nice guy for a Hungarian, and always willing to help.
> 
> Remember, rehabilitation is a 12 step program and you just have to make it one hour at a time.


Having had dinner with our Mad Hungarian friend I can attest that he is both a great guy and a fount of knowledge about wheels. As my friend Charles says there are only Hungarians and those who wish they were.


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## ModFather

Steven said:


> I'm sure that thread is somewhere. I have a hard time finding things on this forum. It isn't the greatest layout, at least with my phone.


Try this thread!


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## Mad Hungarian

Steven said:


> Ahh wheels. I'm not sure what I'll do there. There's not enough difference in appearance between 18's and 19's in my opinion. Depending on if the width is also upped (we don't know that yet, do we?) then stability and braking performance can be enhanced, but at the cost of acceleration (noticable? Probably not), comfort, and range... not to mention $$$.
> 
> I'm sure people have gone over this exhaustively, but I haven't followed. Doing a Google image search I see a Model 3 in real life (r/c) having 235/40 R19's. I'm surprised they're that narrow for a 19. Going over to tiresize.com it looks like we *can* fit anywhere from a 225/70 R14 all the way up to a 325/25 R20 without affecting speedo/sensors at all (ie. identical outer diameter). Taking a 1.5% sensor hit (which may not be wise on a car so reliant on sensors!) we can eek out a 295/25 R21.
> 
> Interesting is that the equiv size 18's are 305/35 R18... considerably wider than the 19's. I'm guessing they'd go with the 235/45 R18 instead, which is 0.4% out and probably acceptable (an even narrower 215/50R18 is also 0.4% out the other way. That would maximize range). Of course, I'm basing this all on the 235/40 R19's being "correct", which is flawed logic, I know. Has anyone confirmed yet what is real?
> 
> I'd be curious about going to 14s  Mushy ride (good and bad thing depending on the quality of roads you drive) and... well, the look would be interesting lol And range would be improved, slightly anyway (unless the 18's are 215's).


Lots to address in this post and happy to do so, but suggest we take it over to the Wheel/tyre discussion thread. Or the Wheel Gap thread as suggested by @ModFather 
Can we kindly get a mod to make this magic move?


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## Mad Hungarian

Daliman said:


> Having had dinner with our Mad Hungarian friend I can attest that he is both a great guy and a fount of knowledge about wheels. As my friend Charles says there are only Hungarians and those who wish they were.


@Daliman you are too kind. With all the depressing politics going on back in my half-ancestral-homeland (yes, I'm only 50%, but that's without question where the Mad comes from) I will take any good PR that I can get


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## garsh

Wheel-related posts have been moved to this nifty new thread.


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## Mad Hungarian

garsh said:


> Wheel-related posts have been moved to this nifty new thread.


Thank you sir.
Hopefully we can keep all the round stuff under one roof so I don't go anymore Mad than necessary trying to keep up.

So as was mentioned by @MelindaV and @ModFather it is indeed just about certain that anything smaller than 17" will not fit due to the size of the brake components. I'm even a little up in the air at the moment about 17" as when the first M3 RC with the Turbine/TravoltaPants/ElvisPants/WhateverWe'reCallingThemThisWeek wheel design first appeared back in late March I initially thought they were 18", and the dark/foggy/low-res wheel portions of the images also made me think that there might be smaller/cheaper floating caliper brakes for the base version. Such is the risk of pontificating with flimsy evidence.
Since then it's been well established that the V-spokes with aero covers are 18" with 235/45R18 tires, the T/TP/EP/WWCTTWs are 19" (can someone please tell me what name the Hive Mind has decreed they shall carry) with 235/40R19 tires, and I never again saw another RC image that suggested the brakes were anything other than a slightly downsized version of the 4-piston monobloc caliper type that we see on S and X
So now assuming those are the only brakes we get on any version it may still turn out that a 17" with _just the right design _will clear those brakes for those seeking ultimate winter traction or the cushiest possible ride. I need to get my hands on a production car to find out.
Have measuring gear, will travel. Anywhere.
My personal plan for my P75D is to go a staggered 19" setup, probably 235/40R19 fronts on 19x8.5 and 265/35R19 rears on 19x9.5. Should fill in those fenders perfectly, maintain a reasonable ride and if paired with lightweight wheels offer a good compromise between range and performance.
Then again if the P75D winds up coming with the Alpha's 20" stagger, and I discover it doesn't ride like an WWII-era Soviet military truck on our local bomb-cratered roads, I may stick with that and just swap the wheels to something from the company repertoire. We shall see.


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## ModFather

Mad Hungarian said:


> My personal plan for my P75D is to go a staggered 19" setup, probably 235/40R19 fronts on 19x8.5 and 265/35R19 rears on 19x9.5. Should fill in those fenders perfectly,


Now you just confused me, which is easy to do. I thought you said in the other thread that it was not advisable to change the OD of the wheel (rim+tire). If that is the case, how do you "fill those fenders perfectly" if the OD remains the same regardless of whether you use 17, 18, or 19 rims? The fender gap will remain constant if the OD is all equal.


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## Mad Hungarian

ModFather said:


> Now you just confused me, which is easy to do. I thought you said in the other thread that it was not advisable to change the OD of the wheel (rim+tire). If that is the case, how do you "fill those fenders perfectly" if the OD remains the same regardless of whether you use 17, 18, or 19 rims? The fender gap will remain constant if the OD is all equal.


Sorry, I meant fill those fenders horizontally, not vertically. I'm OK with the reasonable amount of vertical gap seen on SN1, it's the fact they're just a wee bit too tucked in - especially the rear - that I'd like to fix. Easy enough to do with a bit more width and maybe some offset tweaking.


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## ModFather

Mad Hungarian said:


> Sorry, I meant fill those fenders horizontally, not vertically. ........ it's the fact they're just a wee bit too tucked in - especially the rear - that I'd like to fix. Easy enough to do with a bit more width and maybe some offset tweaking.


Two words: WHEEL SPACERS It is the more cost effective way to address offset than new rims. Bringing those rear tires closer to the fender edge will require fender splash guards, this I know from experience - hello aftermarket   

Another question, some posters have asserted that there are fewer tire choices for 19" rims than 17" or 18" rims. For example, I am 100% committed to Michelin Energy Saver A/S tires for my Tesla 3 (anyone want to purchase my brand new OEM tires at a great price?). They only come in 15, 16, 17, and 18 size. Does a 19" rim severely limit tire selection?


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## garsh

Mad Hungarian said:


> My personal plan for my P75D is to go a staggered 19" setup, probably 235/40R19 fronts on 19x8.5 and 265/35R19 rears on 19x9.5.


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## Jayc

I'd take whatever size it is designed for and not bother with modification. How can anyone other than Tesla even begin to consider all the design scenarios and operating conditions applicable to such a modification. How can you even be sure in an emergency braking situation or collision, the car will react as per safety tests. That's the very reason why changing wheel size voids warranty and insurance around here.


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## Mad Hungarian

Jayc said:


> I'd take whatever size it is designed for and not bother with modification. How can anyone other than Tesla even begin to consider all the design scenarios and operating conditions applicable to such a modification. How can you even be sure in an emergency braking situation or collision, the car will react as per safety tests. That's the very reason why changing wheel size voids warranty and insurance around here.


My day job is to come up with well-integrated wheel/tire upgrades for both OEMs and the aftermarket, so I am fortunate to have a bit of a head start in this department.


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## UncleT

Mad Hungarian said:


> ... I never again saw another RC image that suggested the brakes were anything other than a slightly downsized version of the 4-piston monobloc caliper type that we see on S and X.


It looks to me like the *rear* calipers are the floating type on Elon's car. I think all the RCs I've seen have had this "mismatched" setup.


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## Mad Hungarian

UncleT said:


> It looks to me like the *rear* calipers are the floating type on Elon's car. I think all the RCs I've seen have had this "mismatched" setup.
> 
> View attachment 2197


Confirmed. All RCs spotted have had floating rears, my comments/observations were just about the fronts.


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## Mad Hungarian

ModFather said:


> Two words: WHEEL SPACERS It is the more cost effective way to address offset than new rims. Bringing those rear tires closer to the fender edge will require fender splash guards, this I know from experience - hello aftermarket
> 
> Another question, some posters have asserted that there are fewer tire choices for 19" rims than 17" or 18" rims. For example, I am 100% committed to Michelin Energy Saver A/S tires for my Tesla 3 (anyone want to purchase my brand new OEM tires at a great price?). They only come in 15, 16, 17, and 18 size. Does a 19" rim severely limit tire selection?


At the moment the choices in LRR for 235/40-19 are somewhat limited, but the Michelin Primacy MXM4 is one and does have some LRR in its mix. Rest assured though that when there are several hundred thousand M3s needing replacement tires in a few years there will almost certainly be lots more high efficiency choices available in this size.


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## JBsC6

Aftermarket 20 inch wheels designed with the same look will or could be successful.

Sell two at a time?

Maintaining outside diameter to stock is important for active handling and ABS braking.

I think the rear 19 inch rims are one inch too small for the visual heft of the large rear of the model 3.

The nice part of all four wheels being the same size is people can rotate tires which some people think is important.


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## viperd

What would the differences be between the M3 with factory 18 vs 19 wheels? And how noticeable would they be?


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## Michael Russo

viperd said:


> What would the differences be between the M3 with factory 18 vs 19 wheels? And how noticeable would they be?


Probably not as much if they would have the exact same design which as you know they don't... 

If I'm not mistaken, the 18'' have the V-spoke look while the 19'' are the turbines... 
And I'm not even talking about @ModFather 's beloved UWCs...


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## Jayc

viperd said:


> What would the differences be between the M3 with factory 18 vs 19 wheels? And how noticeable would they be?


Not clear whether you are referring to aesthetic differences or difference in performance. If it is the latter, the following video might be useful.






I have decided it's going to be the 18s for me. Not bothered too much about big alloy looks or precision handling and would gladly trade those for increased safety on wet roads, comfort, reduced noise, reduced wear, better range, cheaper tires,... list goes on.


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## Mad Hungarian

viperd said:


> What would the differences be between the M3 with factory 18 vs 19 wheels? And how noticeable would they be?


Generally speaking the 19" will ride a little more firmly and may offer slightly less range, however they should offer better steering response and higher cornering grip limits in fair weather. And of course look cooler.
EDIT: Vid above is indeed excellent piece on the subject


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## Panda

Mad Hungarian said:


> Generally speaking the 19" will ride a little more firmly and may offer slightly less range, however they should offer better steering response and higher cornering grip limits in fair weather. And of course look cooler.
> EDIT: Vid above is indeed excellent piece on the subject


Function vs form? When will the fight ever end!


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## Panda

Panda said:


> Function vs form? When will the fight ever end!


Dear tesla 3 crew,
Does anyone know if the 19inch wheel reduces significant range or is it only a few km per 100? Thanks in advance to the tech heads out there who know their stuff?


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## Mad Hungarian

Panda said:


> Dear tesla 3 crew,
> Does anyone know if the 19inch wheel reduces significant range or is it only a few km per 100? Thanks in advance to the tech heads out there who know their stuff?


My shooting-in-the-dark opinion here is it won't be a huge difference. The section width remains the same in both sizes and they are both using efficiency-oriented tires. The 18" will definitely have an advantage due to its lighter weight and better aerodynamics, but I'm guessing it will be somewhere in the 2% range.


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## KennethK

@Mad Hungarian , could you tell if the Continentals on SN1 were the same as the RCs? And are they good tires in your opinion?


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## Mad Hungarian

KennethK said:


> @Mad Hungarian , could you tell if the Continentals on SN1 were the same as the RCs? And are they good tires in your opinion?


Strangely as you were writing this I was out running another range test with some Continental PureContacts on my Volt...
I'm not sure if I've seen any pics of SN1 that are clear/close enough to confirm they are the same as the ones on the RCS. But I do have a lot of respect for the brand in general and am especially amazed at how lightweight many of their tires are (an often overlooked performance benefit).
Let me get back to you...


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## ModFather

Panda said:


> Dear tesla 3 crew,
> Does anyone know if the 19inch wheel reduces significant range or is it only a few km per 100? Thanks in advance to the tech heads out there who know their stuff?


So much depends on the comparative weights of the 18" and 19" rims. We don't know what the weights are of those rims yet except that the 19" will probably be heavier than the 18". Depending on that weight difference, the difference in range could be negligible to up to maybe 5%. This difference will only be noticeable on longer trips. Around town, you won't be able to tell the difference except for a somewhat stiffer ride.

I will be purchasing the 18" rims because of better ride quality, some better range compared to 19", and lower cost of replacement tires. I am hoping for at least a 5% range advantage over the 19s when I drive on longer trips and use the included Unique Wheel Covers on the 18s (12 to 15 miles more minimum). As I have said in other threads, I am going to switch to Michelin LRR Energy Saver A/S tires. I know from personal experience that these tires give me an additional 5% increase in range compared to other tires (but they don't come in 19"). So all things considered, I am shooting for a total 10% better range, compared to 19s, on longer trips!


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## Panda

ModFather said:


> So much depends on the comparative weights of the 18" and 19" rims. We don't know what the weights are of those rims yet except that the 19" will probably be heavier than the 18". Depending on that weight difference, the difference in range could be negligible to up to maybe 5%. This difference will only be noticeable on longer trips. Around town, you won't be able to tell the difference except for a somewhat stiffer ride.
> 
> I will be purchasing the 18" rims because of better ride quality, some better range compared to 19", and lower cost of replacement tires. I am hoping for at least a 5% range advantage over the 19s when I drive on longer trips and use the included Unique Wheel Covers on the 18s (12 to 15 miles more minimum). As I have said in other threads, I am going to switch to Michelin LLR Energy Saver A/S tires. I know from personal experience that these tires give me an additional 5% increase in range compared to other tires (but they don't come in 19"). So all things considered, I am shooting for a total 10% better range, compared to 19s, on longer trips!


Thanks to mod and mad for your replies


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## Mad Hungarian

Mad Hungarian said:


> Strangely as you were writing this I was out running another range test with some Continental PureContacts on my Volt...
> I'm not sure if I've seen any pics of SN1 that are clear/close enough to confirm they are the same as the ones on the RCS. But I do have a lot of respect for the brand in general and am especially amazed at how lightweight many of their tires are (an often overlooked performance benefit).
> Let me get back to you...


So after going a bit Zapruder on the SN1 video shot in the factory parking lot, I'm feeling pretty certain that it's wearing the same Conti ProContact RX tires that we've seen on the RC cars. Screen cap:








Verrrryy similar sidewall markings and the small amount of tread visible on the shoulder seems to match.
This appears to be a non-runflat version of the the ProContact RX SSR which has already appeared on a few other vehicles as OEM. Some folks have criticized the SSR version as being noisy, but removing the runflat requirement would allow them to achieve better NVH characteristics and I'm sure Tesla would have been working hard with Conti to get this version dialed-in exactly how they want it for the M3, and the sidewall markings on the RC's show it has their Conti Silent tech inside, so that ought to help.
I'd expect it to be a good middle-of-the-road blend of range, comfort and performance.


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## Michael Russo

Mad Hungarian said:


> So after going a bit Zapruder on the SN1 video shot in the factory parking lot, I'm feeling pretty certain that it's wearing the same Conti ProContact RX tires that we've seen on the RC cars. (...)
> This appears to be a _non-runflat_ version of the the ProContact RX SSR which has already appeared on a few other vehicles as OEM. (...)


'non-runflat' = spare in the trunk?


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## ModFather

Michael Russo said:


> 'non-runflat' = spare in the trunk?


No, 'non-runflat' = insurance policy in glove box.

Some people think a can of "Slime" and a bicycle pump will do the trick in a TESLA 3, but I am very skeptical. I know the Chevy SSR pickup included a can of Slime and an onboard 12v compressor and that didn't work for Shinola in real life and owners just started carrying donut spares in the rear bed on longer trips. I, for one, am not going to worry about it since I have roadside assistance on my insurance.


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## mig

ModFather said:


> No, 'non-runflat' = insurance policy in glove box.
> 
> Some people think a can of "Slime" and a bicycle pump will do the trick in a TESLA 3, but I am very skeptical. I know the Chevy SSR pickup included a can of Slime and an onboard 12v compressor and that didn't work for Shinola in real life and owners just started carrying donut spares in the rear bed on longer trips. I, for one, am not going to worry about it since I have roadside assistance on my insurance.


I have had to use the 12V pump/sealant kit on the BMW i3 once. It didn't "repair" the tire, but sealed enough that I could limp along to a local tire repair shop (they were able to repair the tire).

I got another flat after hitting a pothole a few months later and had to wait for a tow. I was on the side of the freeway for 90 minutes waiting for a tow truck to get 2 miles to the tire shop. (the drawback of roadside assistance). At least 3 nice people stopped to see if I needed gas or anything


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## ModFather

mig said:


> I have had to use the 12V pump/sealant kit on the BMW i3 once. It didn't "repair" the tire, but sealed enough that I could limp along to a local tire repair shop (they were able to repair the tire).
> 
> I got another flat after hitting a pothole a few months later and had to wait for a tow. I was on the side of the freeway for 90 minutes waiting for a tow truck to get 2 miles to the tire shop. (the drawback of roadside assistance). At least 3 nice people stopped to see if I needed gas or anything


Tow truck should have taken surface streets for a 2 mile call during rush hour which extends from 5am to 11am and 2pm to 8pm on Los Angeles freeways! I had to think about the nice people who wanted to know if you needed gas..............................
Then I noticed you were driving an i3!









Out of curiosity, what size wheels do you have on the i3? The larger the rim, the more danger there is from potholes doing damage. I have been told that putting sealant in a tire to affect a temporary repair, ruins the tire and needs to be replaced. Any experience with that?


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## mig

ModFather said:


> Out of curiosity, what size wheels do you have on the i3? The larger the rim, the more danger there is from potholes doing damage. I have been told that putting sealant in a tire to affect a temporary repair, ruins the tire and needs to be replaced. Any experience with that?


The BMW i3 has 19" wheels (I believe) with these interesting skinny tires which BMW specially commissioned Bridgestone to make. So they're about $200 to replace. Fun!

The tire shop told me the sealant was no problem and would not ruin rims nor tires. It is messy though, so I'm sure tire shops don't appreciate it! (I do remember hearing this rumor when I drove a LEAF though, so take my limited knowledge with grain of salt)

More information on the i3 tires here:
https://bmwi3.blogspot.com/2014/02/bmw-i3-wheels-and-tires-what-you-need.html


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## KennethK

The tires on the 18" wheels are Michelin Primacy MXM 4.


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## garsh

KennethK said:


> The tires on the 18" wheels are Michelin Primacy MXM 4.
> View attachment 2217


Those have a pretty good reputation as replacement tires on the Leaf forums.


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## ModFather

KennethK said:


> The tires on the 18" wheels are Michelin Primacy MXM 4.





garsh said:


> Those have a pretty good reputation as replacement tires on the Leaf forums.


But not a good reputation on the Prius fora. I don't believe the Primacy are LRR tires. There were complaints about road noise from those tires as well as being not as long a service life as the Energy Savers. YMMV.


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## Thomas Mikl

Guys check the other thread where I talk about wheel aerodynamics. The weight of the wheel will be nearly irrelevant (unless the 19 inch is made from led)... aerodynamics and rolling resistance of the rubber touching the ground will make more difference.


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## EValuatED

Thomas Mikl said:


> Guys check the other thread where I talk about wheel aerodynamics. The weight of the wheel will be nearly irrelevant (unless the 19 inch is made from led)... aerodynamics and rolling resistance of the rubber touching the ground will make more difference.


Agree, re: rolling & range... handling can be better if lighter (than led)? But from the looks of them I can't imagine there's *too* much difference in weight between the 18s & 19s?


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## Thomas Mikl

Honestly I think both will be around 16-18 lbs.


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## ModFather

Thomas Mikl said:


> Guys check the other thread where I talk about wheel aerodynamics. The weight of the wheel will be nearly irrelevant (unless the 19 inch is made from led)... aerodynamics and rolling resistance of the rubber touching the ground will make more difference.


Tomas, I went back and read your scholarly post. I see that you calculated for air turbulence based on no wheel compared to rim and tire, but I see no reference to wheel weight. There have been consistent studies that show that "unsprung weight" (rim and tire) are the biggest contributor to reduced range. Yes, other factors - rim design, rolling resistance of tire, tire width, wheel tucked well inside the fender - all play a part in efficiency, but unsprung weight is primary. Here is what Internet poster @F8L has to say:

_Wheel weight is important but so is offset and aerodynamics. If you change the offset from stock by decreasing offset such that the wheel sticks out into the airstream then you could lose mpg. Wheel upsizing can also reduce mpg quite drastically despite keeping wheel weight the same. In the Prius world, upsizing from a 15" to 17" wheel (maintaining OE rolling diameter) can drop your mpg by as little as 3mpg to as much as 8mpg depending on driving style.

Tires are much more complex and weight doesn't tell the whole story. You're best bet is to stick with a low rolling resistance tire that has been tested against other LRR tires so you can see how they rank. Not all LRR tires are created equal so one tire may provide much better fuel efficiency than another. Some of the best: Energy Saver A/S, Ecopia EP100 and EP422, Assurance Fuel Max, dB Super E-Spec, Nokian enTYRE, Primacy MXM4, etc.. 
_​Anecdotal experience by Prius drivers showed that MIchelin Energy Saver A/S tires were the best of the best. They don't come in a larger diameter than 18" This is why I will be selecting the 18" TESLA 3 OEM rims and run them with the UniqueWCs on longer trips. I think I can get close to 10% more range than the 19s with this setup on long trips.


EValuatED said:


> Agree, re: rolling & range... handling can be better if lighter (than led)? But from the looks of them I can't imagine there's *too* much difference in weight between the 18s & 19s?


Obviously, nobody knows yet what the weight of the rims will be, but to my eye, the 19s look like they will be at least 5 lbs. heavier than the 18s. And this difference in weight is substantial and significant.



Thomas Mikl said:


> Honestly I think both will be around 16-18 lbs.


Tomas, I think you are being way too optimistic. My guess is that the 18s will be about 22 lbs, and the 19s about 30 pounds. The 19" rims for the MS, which are similar to the model 3 rims, are 30 lbs each.


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## Mad Hungarian

Thomas Mikl said:


> Guys check the other thread where I talk about wheel aerodynamics. The weight of the wheel will be nearly irrelevant (unless the 19 inch is made from led)... aerodynamics and rolling resistance of the rubber touching the ground will make more difference.


Your assertion is correct for steady-state highway driving. But ONLY for that condition.
In the constant stop-start environment of low speed city driving the reverse is true; aerodynamics become essentially irrelevant, its all about the weight.
Yes, regen will recoup a little of the extra inertia of the heavier wheel, but you're still going to take a noticeble hit.

So one must carefully consider where the bulk of their driving is done in order to best prioritize these characteristics.
Its obvious now Tesla has come to the same conclusion as the other OEMS looking for the ultimate way to serve both masters: run a lightweight open alloy wheel and achieve the aero properties you need with a much lighter plastic cover.


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## Mad Hungarian

ModFather said:


> Tomas, I went back and read your scholarly post. I see that you calculated for air turbulence based on no wheel compared to rim and tire, but I see no reference to wheel weight. There have been consistent studies that show that "unsprung weight" (rim and tire) are the biggest contributor to reduced range. Yes, other factors - rim design, rolling resistance of tire, tire width, wheel tucked well inside the fender - all play a part in efficiency, but unsprung weight is primary. Here is what Internet poster @F8L has to say:
> 
> _Wheel weight is important but so is offset and aerodynamics. If you change the offset from stock by decreasing offset such that the wheel sticks out into the airstream then you could lose mpg. Wheel upsizing can also reduce mpg quite drastically despite keeping wheel weight the same. In the Prius world, upsizing from a 15" to 17" wheel (maintaining OE rolling diameter) can drop your mpg by as little as 3mpg to as much as 8mpg depending on driving style.
> 
> Tires are much more complex and weight doesn't tell the whole story. You're best bet is to stick with a low rolling resistance tire that has been tested against other LRR tires so you can see how they rank. Not all LRR tires are created equal so one tire may provide much better fuel efficiency than another. Some of the best: Energy Saver A/S, Ecopia EP100 and EP422, Assurance Fuel Max, dB Super E-Spec, Nokian enTYRE, Primacy MXM4, etc..
> _​Anecdotal experience by Prius drivers showed that MIchelin Energy Saver A/S tires were the best of the best. They don't come in a larger diameter than 18" This is why I will be selecting the 18" TESLA 3 OEM rims and run them with the UniqueWCs on longer trips. I think I can get close to 10% more range than the 19s with this setup on long trips.
> 
> Obviously, nobody knows yet what the weight of the rims will be, but to my eye, the 19s look like they will be at least 5 lbs. heavier than the 18s. And this difference in weight is substantial and significant.
> 
> Tomas, I think you are being way too optimistic. My guess is that the 18s will be about 22 lbs, and the 19s about 30 pounds. The 19" rims for the MS, which are similar to the model 3 rims, are 30 lbs each.


18 lbs with the cover would be a stellar result and would at bare minimum need flow-formed barrels to reach the wheel load rating this car is going to require.
16 lbs would be incredible but is only achievable if they go to fully forged construction. This is big $$$. Even then I don't know if they could hit their impact and fatigue targets at that weight, which I assume are just as extreme or more so than the OEMs we currently build for.


----------



## Thomas Mikl

The Coefficient for a wheel is cr = d/R is about 0.011
Fr = cr * Fn
So yes the weight is the thing for stop and go.
However lets assume a Model S is prolly 1200 lbs of the battery pack and complete model s around 4400 lbs which is around 2000 kg.
So lets roughly say Fr = 0.011 * (2000 * 9.8) is around 215.6



4 Wheels lets go with 30 lbs each = 120 lbs.
Now lets say the 18s are really 10 lbs less weight that would make it 80 lbs.
So we are saving 40 lbs.

That would be a total save of 1% saved.
So our new Fr = 0.011 * (1960 * 9.8) = 211,2

That would mean below 2% in our roughtimation.

Now you might say > well that is 2% range. Well sorry it is not. As soon as the wheel is turning (and you have loads of torque to make it roll) that Fr becomes irrelevant (well not really but it goes into standard rolling force) whereas air is actually going to be exponentially playing a role. Even at 15mph the air pressure will equalize roughly any downforce that plays in.

Hence it is always a good idea to make a car more aerodynamic over saving weight. Of course saving weight is good, but not the real thing...

As proudly shown by Hyundai Ioniq. It has the same battery as the i3 but it is A LOT heavier and has much worse tires. Nonetheless it gets roughly 10-20% more range, simply because it is A LOT more aerodynamic.
When asked the chief designer of Hyundai said: Before investing into a carbon chassis, we asked a physicist if it is worth it and he said No, but the cash into wind tunnel testing.


----------



## ModFather

Thomas Mikl said:


> model s around 4400 lbs which is around 2000 kg.
> So lets roughly say Fr = 0.011 * (2000 * 9.8) is around 215.6
> 
> 4 Wheels lets go with 30 lbs each = 120 lbs.
> Now lets say the 18s are really 10 lbs less weight that would make it 80 lbs.
> So we are saving 40 lbs.
> 
> That would be a total save of 1% saved.
> So our new Fr = 0.011 * (1960 * 9.8) = 211,2


Tomas, I can't dispute your formulae since I am not familiar with the math. But it appears you are mixing kgs with lbs in your math (2000kgs - 40lbs = 1960kgs). So I don't know.

Rather than pick nits, I will say that there have been tests on the track where a 16" and 17" wheel (rim plus tire) with the same O.D. have been compared - same rim only in larger size and same tire in lower profile size and the difference was about 2% average for both low speed (city driving) and high speed (highway driving). But this test was only part of the story. As the rim gets larger say from 18" to 19" the difference increases exponentially. in the case of model 3 you have different rim designs with the 18" being more aerodynamic than the 19". And if good LRR tires are used that also gives an advantage. So what I am saying is that each one of these factors (if not a big deal individually) helps incrementally, and they add up to achieve better range.

I think the number one way to achieve better range in both city and highway driving is drive conservatively by "hypermiling". I read somewhere that TESLA bases their predicted range on highway speeds of 60 to 65 mph. They also avoid hard acceleration and hard braking in city driving. We consistently get 70 to 80 mpg in our Prius Plug-in with about a 50/50 mix in both city/highway driving by hypermiling.

So to repeat myself, I am hoping to get 10% better range than 19" rims in both city and highway range by the following:
1. drive conservatively by hypermiling and regenerating as much as possible in both city and highway
2. go with OEM 18" rims and use the UniqueWCs especially on the highway
3. switch to the best LRR tires available at this time


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## Mad Hungarian

Thomas Mikl said:


> The Coefficient for a wheel is cr = d/R is about 0.011
> Fr = cr * Fn
> So yes the weight is the thing for stop and go.
> However lets assume a Model S is prolly 1200 lbs of the battery pack and complete model s around 4400 lbs which is around 2000 kg.
> So lets roughly say Fr = 0.011 * (2000 * 9.8) is around 215.6
> 
> 4 Wheels lets go with 30 lbs each = 120 lbs.
> Now lets say the 18s are really 10 lbs less weight that would make it 80 lbs.
> So we are saving 40 lbs.
> 
> That would be a total save of 1% saved.
> So our new Fr = 0.011 * (1960 * 9.8) = 211,2
> 
> That would mean below 2% in our roughtimation.
> 
> Now you might say > well that is 2% range. Well sorry it is not. As soon as the wheel is turning (and you have loads of torque to make it roll) that Fr becomes irrelevant (well not really but it goes into standard rolling force) whereas air is actually going to be exponentially playing a role. Even at 15mph the air pressure will equalize roughly any downforce that plays in.
> 
> Hence it is always a good idea to make a car more aerodynamic over saving weight. Of course saving weight is good, but not the real thing...
> 
> As proudly shown by Hyundai Ioniq. It has the same battery as the i3 but it is A LOT heavier and has much worse tires. Nonetheless it gets roughly 10-20% more range, simply because it is A LOT more aerodynamic.
> When asked the chief designer of Hyundai said: Before investing into a carbon chassis, we asked a physicist if it is worth it and he said No, but the cash into wind tunnel testing.


Thomas I think there's something you're not taking into account here, wheels are not static weight.
And as with all things that we want to start rotating from a dead stop we have to overcome inertia. So any weight added to the wheels creates two types of additional energy demands:
1. That of overcoming the increased total static weight of the vehicle
2. That of overcoming the increased inertial resistance of the increased wheel mass
Now the exact additional energy drain the inertial effect creates will vary with where the additional mass is in the wheel (the farther away from the center, the worse the effect becomes) but an average conservative figure for most designs is x2.
So increasing the weight of the 4 wheels in your example by 40 lbs would be equivalent to _addidng 80lbs of static weight_. And if the tire used is heavier as well (which can happen frequently when plus-sizing to a larger diameter wheel as lower profile tires required often have more heavily reinforced sidewalls) then effect can become quite a bit more significant as this additional mass is even further out from the center point. And every time you want to increase the car's speed it needs to deal with this. Over and over again.
But you don't have to take my word for it... have a look at some real-world testing Car and Driver performed on the effects of plus-sizing wheels and tires.
Now of course there are other variables here are the section width varied from 205 up to 235, and even though they used the same model of tires for all four sizes there are bound to be some variables in the exact rolling resistance charicteristics of each. But just the same, we can see that adding 14 lbs per corner results in a 10% increase in fuel consumption. If we were to average the results that means a 10 lbs increase you propose would result in a 7% increase. Even if we assume that an EV will recoup about 50% of this additional inertial mass penalty when it regens to slow down, we still arrive at an average value of 3.5% more energy required for a 10 lbs per wheel/tire increase. Feeling even more generous, I will take another percentage point off that because the Golf used for their test weighs about 70% of what we expect a Model 3 to weigh, so the extra static weight penalty as a function of the total vehicle weight will be about 30% less. But the additional energy required to overcome the inertia of the heavier wheels isn't subject to that same relationship so we cannot apply that same discount. In fact it may be felt more in an EV, as the rotational mass of the components their drivetrains is far, far less than it is in any ICE, so here the wheels play a much bigger role as viewed as a total percentage of drivetrain inertial mass.

So if we leave the aero component as a constant, in the end I say increasing weight by 10 lbs a corner on an EV used in any kind of normal drive cycle like the one C/D used for their test is going to cost you at least 2.5% range. And again,based on the CD results, this is being pretty conservative.


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## Thomas Mikl

Indeed you are right ModFather I mixed that up 40 lbs is about 18kg, so the savings is actually less than 1%.

MadHungarian you are right the wheel turning creates centripetal force. Distribution of the force is however constant and the most weight is not on the outside of the wheel (there is rubber there). Of course you increase that force when the alloy gets larger and the rubber gets less ... However the difference in Centripetal force due to diameter and weight is negligable as the friction force, the moving force and the momentum of the car are all magnitudes higher.
I can recommend reading the book by Springer, Basic Forces in Car Dynamics
It explains all that very very well.
Or you can also check out the Youtube Channel "Engineering Explained", he has a lot of cool videos on the topic, not EV specific as he is a petrol head, but good nonetheless.


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## Panda

Dear wheel experts,
I'm trying to decide between the 18 vs 19 in terms of longer term efficiency loss. I drive about 40km per day at 80km/h ( My guesstimate is about 7 to 8 kw in the T3). However, if the range is only around 2-3 percent loss difference between 18 vs 19 inch wheels, wouldn't other factors like a dirty car or full roof rack when going on holiday have an equal or greater drag force than the wheels. Aeroplanes are polished and lose up to 4 percent fuel if they are left dusty. Maybe someone can give a comparative efficiency table on common things we do to cars eg windows open vs closed or leaving 30kg sport gear in the boot and the effect on range...Anyone up the challenge?


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## Thomas Mikl

If you start to workout and weight 10 lbs less it will help, if you do not leave all that sports gear in the car all the time it will help.
Now with dust you are stretching it, because we do not travel 600mph with a car, but sure it helps if the car shines.
But most important if you drive economically it will do a lot more than the wheels.
Also if you replace the tires if they get bald sooner rather than later and again with a high efficiency tire, then it will make more difference than the wheel.
My guess is still that it will be around 2% loss for the 19inch TOPS and prolly other factors will make more.
For example care for your battery, having a garage over leaving it in the elements over night, driving habbits (not flooring it all the time) not taking corners at max speed but with g-forces not ripping your head off.
You can easily get back those 2% by those things.
I will def. go for the bigger ones....

There is actually a shark skin like fabric you can put over the car, that is said to increase range  I doubt it will make 2% but it is hellish expensive and makes you feel better hehe


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## ModFather

Panda said:


> I'm trying to decide between the 18 vs 19 in terms of longer term efficiency loss. I drive about 40km per day at 80km/h


For your personal use, it is not going to make any significant difference on range. As Elon would out it, "you won't care." In your case, the best way to increase range is to drive conservatively (as @Thomas Mikl says).

The things you should consider with 19" wheels are,
1. higher replacement cost of tires
2. somewhat less comfortable, stiffer ride
3. greater exposure to tire damage from potholes, road debris, etc.
4, shorter tire life


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## garsh

FYI, on my Leaf, I went from the stock 16"x6.5" wheels to 17"x7.5" front, 17"x8" rear.
My efficiency dropped by about 10%.
Which kind of sucks on a car that's only EPA-rated for 99 miles. 


Panda said:


> However, if the range is only around 2-3 percent loss difference between 18 vs 19 inch wheels, wouldn't other factors like a dirty car or full roof rack when going on holiday have an equal or greater drag force than the wheels.


There's a mythbusters episode where they compare dirty & clean car mileage. The myth was that a dirty car would be more efficient due to the "dimpled golf ball" effect. It was less efficient, but I think the result may have had more to do with the added weight of the mud than the aerodynamic changes.

Adding weight will have a large effect. But remember, these effects are *additive*. It's not like they get cancelled out because you're doing something else that decreases mileage. So if you're worried about mileage, get the lighter wheels/tires (which tend to be the smaller diameter ones).


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## ModFather

In the latest photo dump today, I noticed the red dot on the MIchelin Primacy tire. Having seen that red dot before on other tires, I decided to Google it for the meaning. It apparently is an indicator mark that helps with tire balancing. I think the red mark adds nothing to the cars appearance. I will probably get some black tire paint and paint it out. Any comments from the cognizant!


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## TrevP

Michelin Primacy green Acoustic tires in use on the white RC. Runs consistent with Tesla using Contis with foam inserts to reduce tire noise.










Bjørn Nyland posted a picture on FaceBook of his Michelins pulled from his Model X. Clearly shows the foam insert


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## garsh

That red dot on the tire is supposed to be lined up with the valve stem when mounting the tire.
Bad Tesla Service Technician! Bad!


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## Mad Hungarian

Thomas Mikl said:


> MadHungarian you are right the wheel turning creates centripetal force. Distribution of the force is however constant and the most weight is not on the outside of the wheel (there is rubber there).


I must respectfully disagree.
If we split a typical cast alloy wheel into its three main structural components, the center/mounting pad, the spokes, and the barrel/rim, we will see that the heaviest component is the barrel/rim segment. This part accounts on average for about 40% to 45% of an a cast alloy wheel's total weight. And your assertion "most weight is not outside the wheel" is also false. Pulling the weight data for the 38 different models of 235/40R19 summer and all season tires in our system I arrive at an average of *24.5 lbs*. Same excersise for the 148 different 19x8.0 wheels we have recorded reveals an average of *25.4 lbs.* So in the case of the Model 3 19" sizing, the tire is nearly equal in weight to the wheel. But because its mass is concentrated even farther away from the axis of rotation its effect is greater.



Thomas Mikl said:


> Of course you increase that force when the alloy gets larger and the rubber gets less ... However the difference in Centripetal force due to diameter and weight is negligable as the friction force, the moving force and the momentum of the car are all magnitudes higher


_Negligible_? Really?
Again, I don't think you fully appreciate the effect this additional rotating mass has. The Car and Driver test I cited showing what a significant effect the increased weight of the wheel tire assemble has on energy consumption. However it did have the additional complication of using different tire and wheel sizes. As the main point we're trying to debate here is what is the total effect of going from 18" to 19" on the Model 3, I still think it's a very valuable study.
But since for the moment it's now devolved into a debate over whether the weight has any affect at all we need something much more specific. And that would be an experiment where the ONLY variable was the wheel weight. Luckily the good folks at Tire Rack - one of the world's most renowned experts in testing wheels and tires - performed this exact experiment, and even better on a car similar to the size and class of our future one, a 3 series BMW. Better still, the weight difference between the heavy and the light wheel is, you guessed it, exactly 10 lbs.
Read away: https://www.tirerack.com/wheels/tech/techpage.jsp?techid=108

So, as we see in their results, by doing nothing other than increasing wheel weight by 10 lbs per corner we see a 2% increase in energy consumption.

Thomas, I just want to say I really appreciate your enthusiasm in defending your position here, as well as your willingness to spend the time showing the science behind your theories. I more than anyone love to learn from others' knowledge and experiences in all kinds of fields. And I just love a civilized debate on an interesting subject. However you need to be careful in proclaiming that the theoretical results of your calculations are absolute in the absence of any test data to support it. Many people might take that at face value and wind up making a bad choice. At the end of the day this one is all about what works in the real world, and that is not always as easy as the basic equations suggest.


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## Mad Hungarian

Thomas Mikl said:


> Also if you replace the tires if they get bald sooner rather than later and again with a high efficiency tire, then it will make more difference than the wheel


Just a clarification here, all tires actually use LESS energy as they wear due to both the reduction in overall mass and parasitic energy losses from tread block movement.
Michelin has actually started a program to convince people to keep their tires on the car _longer _in an effort to take advantage of this. Now that may seem a bit insane when your business is selling more tires, but there's a method to their madness, they're trying to make a case to regulators that tires should not only be tested and certified when new, but also when used. This would benefit them as they do already put a lot of effort into engineering tires that perform well to the bitter end. Even so, I still applaud them for the effort of raising the bar for all manufacturers in making sure tires are indeed safe as they go past middle age and especially for doing their part to stop tires being needlessly recycled, or worse, going into landfills.


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## Mad Hungarian

garsh said:


> That red dot on the tire is supposed to be lined up with the valve stem when mounting the tire.
> Bad Tesla Service Technician! Bad!


LOL!
Actually we might not have to scold said tech, the red dot is the tire's "high point" indicator, which is supposed to be matched to the wheel's lowest point to make for an assembly with the best possible uniformity (closest to perfectly round, in non-tire jargon). Some tires also have a yellow dot that indicates the lightest point of the tire, and that would be the one that should be aligned with the valve stem, which is usually the heaviest point of the wheel.
Yokohama has a good little tech piece on this here.
The general consensus is if you have markings that show the tire's high point and the wheel's low point, then that takes precedence over the weight match method (which can be more easily be corrected with balance weights). If not, then yellow-dot-to-valve. Strangely I _have _seen some journal articles that recommend putting the red dot to the valve, even while acknowledging that it's the uniformity marker, but without any further explanation. Manufacturer documents pretty much all agree with the one from Yoko.
Now the dots are nice, but I far prefer relying on balancers that either use optical or road-force measurement to check what the wheel/tire assembly is REALLY doing. No guesswork and if anything is out of whack these machines will tell you how to re-position the tire on the rim for the best possible result.


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## Mad Hungarian

ModFather said:


> In the latest photo dump today, I noticed the red dot on the MIchelin Primacy tire. Having seen that red dot before on other tires, I decided to Google it for the meaning. It apparently is an indicator mark that helps with tire balancing. I think the red mark adds nothing to the cars appearance. I will probably get some black tire paint and paint it out. Any comments from the cognizant!


Knock yourself out, once the tire's installed and used those dots are pretty much just along for the ride.
Unless there's some secret regulation I'm unaware of, like that tag on mattresses. If so I will then delete this post and disavow any knowledge of this conversation talking place. Those Mattress Police guys are worse than the Stasi.


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## ModFather

Mad Hungarian said:


> like that tag on mattresses.


Having sold mattresses for 10 years, long ago, the first thing I do today is tear the tag off the mattress! I know you are not going to believe this, but you know those notices that say, "do not fold, spindle, or mutilate"? The first thing I do......................................yeah, you guessed it!


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## UncleT

Mad Hungarian said:


> LOL!
> Actually we might not have to scold said tech, the red dot is the tire's "high point" indicator, which is supposed to be matched to the wheel's lowest point to make for an assembly with the best possible uniformity (closest to perfectly round, in non-tire jargon). Some tires also have a yellow dot that indicates the lightest point of the tire, and that would be the one that should be aligned with the valve stem, which is usually the heaviest point of the wheel.
> Yokohama has a good little tech piece on this here.
> The general consensus is if you have markings that show the tire's high point and the wheel's low point, then that takes precedence over the weight match method (which can be more easily be corrected with balance weights). If not, then yellow-dot-to-valve. Strangely I _have _seen some journal articles that recommend putting the red dot to the valve, even while acknowledging that it's the uniformity marker, but without any further explanation. Manufacturer documents pretty much all agree with the one from Yoko.
> Now the dots are nice, but I far prefer relying on balancers that either use optical or road-force measurement to check what the wheel/tire assembly is REALLY doing. No guesswork and if anything is out of whack these machines will tell you how to re-position the tire on the rim for the best possible result.


Yes, my current Enkei wheels have the dot and none of them are in the same location in relation to the valve stem. The couple times I had someone else rotate my tires I used this to confirm that they rotated them properly.


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## mig

Thomas Mikl said:


> Before investing into a carbon chassis, we asked a physicist if it is worth it and he said No, put the cash into wind tunnel testing.


This was great. I pictured Hyundai engineers dumping bags of cash in front of giant fan blades


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## Thomas Mikl

Actually if you factor that in MadHungarian due to rotational inertia, you are of course right that less rotational inertia is better aka less weight on the outside of the wheel (any mm counts in theory). So if you count for usual wheel rotation you are of course right that wheels weight counts more.
But a usual factor is 1:2, so ever 1 lbs you shave of the wheel (on the very outside) is approx. worth 2lbs of weight savings driving at an average 40-50mph.
So yes saving that 4 lbs from the 18s to the 19s will win you back a max of 10 lbs per wheel "in perfect laboratory environments".
So again yes you could potentially save 40-60 lbs of the car counting for rotational inertia.
Compared to aerodynamic forces on the wheel and the car weighing in (model s) at over 4000 lbs, we are still talking 1% in real world conditions due to weight. 
Same can be said for all rotating parts of the car, so saving weight inside the rotating drivetrain is also a good thing.

However I still am 100% sure checking the science, that if you go with aftermarket alloys that are 10 lbs lighter but have worse aerodynamics, you are in total worse in range.


----------



## garsh

Thomas Mikl said:


> However I still am 100% sure checking the science, that if you go with aftermarket alloys that are 10 lbs lighter but have worse aerodynamics, you are in total worse in range.


For a steady-state speed, sure.


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## garsh

Mad Hungarian said:


> Sorry, I meant fill those fenders horizontally, not vertically.


Here's a little visual aid.
On the left, a Nissan Leaf with OEM 17"x6.5" wheel.
On the right, a Nissan Leaf with 17"x8" wheel.


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## Panda

Thanks everyone for their comments on comparing 18 vs 19 wheels


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## Mad Hungarian

garsh said:


> Here's a little visual aid.
> On the left, a Nissan Leaf with OEM 17"x6.5" wheel.
> On the right, a Nissan Leaf with 17"x8" wheel.


Excellent demonstration. 
The cool kids refer to this lateral positioning as Stance, and to my eye you've got yours dialed in just about perfectly.


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## ModFather

garsh said:


> Here's a little visual aid.
> On the left, a Nissan Leaf with OEM 17"x6.5" wheel.
> On the right, a Nissan Leaf with 17"x8" wheel.


I prefer the look of the car on the right. In my opinion that improves the look of a car more than simply running 18" rims with the same offset on the car on the left. You did say that your car on the right did cost you a 10% penalty in range. I presume you also installed wider tires and rims with a different design too. So that 10% penalty was caused by three factors:
1. different offset to move wheels out closer to the fender line
2. wider width tires
3. less aerodynamic rims

I want to do something on my TESLA similar to what you did on your LEAF, but not at a cost of 10% in range. I apologize for keep citing the anecdotal experience of the "cool guys" with a Prius, but there is a lot of trial and error experience there - to keep their cars efficient but also looking "cool". Here is what they did to minimize reducing range:
1. OEM tire size was not changed- narrower tires are generally more efficient than wider tires. If tires were changed, then it was only the rear tires that were made wider and the front tires were OEM size.
2. Lighter rims were used if possible, but is was difficult to find a rim lighter than the OEM rim, especially at a reasonable price, so most just left the OEM rims on.
3. Change tires to the most efficient LRR tire
4. @Thomas Mikl is right, the front wheels are more critical than the rear wheels as far as aerodynamics! So, offset was adjusted with wheel spacers, 12mm (1/2") in the front and 25mm (1") in the rear. There are good and bad wheel spacers and two different things known as wheel spacers!!! There's one type that is installed over lugs like a giant washer and the lugs go threw them and the wheels. These are bad since you reduce the amount of "bite" when torquing down the lug nuts. The spacers recommended are also known as wheel adapters and are attached to the hub via your original lugs and nuts then torqued to spec. They then have their own set of lugs and nuts that hold the wheel to them. These are good. It is also important to purchase high quality adapters from a reputable company, not Chinese crap off of Ebay.

Using these techniques, range reduction was limited to maybe 2-3%, certainly livable. I am going to employ the four strategies above- OEM size tires on front and perhaps a bit wider tire on rear, use stock 18" V-spoke rims, change out to Michelin Energy Saver tires, use wheel adapters on rear and maybe the front, plus use the Unique WCs at least on longer trips. I am confident I can match TESLA projected range with these modifications and also enjoy a minimum 10% range advantage over the 19" turbine wheels with wider tires.

I admit this is pure speculation on my part at this time, but it is based on some real experience. I am excited to experiment on my car and record the results over period of time. This is going to be fun!


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## garsh

ModFather said:


> So that 10% penalty was caused by three factors:
> 1. different offset to move wheels out closer to the fender line
> 2. wider width tires
> 3. less aerodynamic rims


I'd guess that #1 & #3 had minimal effects.
#2 is huge, because all else being equal, a wider tire has more rolling resistance.

I think there are two other large factors affecting efficiency:
4. The larger wheels & tires are much *heavier* than OEM.
5. The OEM tires were LRR - the new tires are *not LRR*.

And another small factor:
6. I went with a slightly larger-diameter tire than stock in the rear (235/50R17 vs OEM sizes of 215/50R17 or 205/55R16).
This will result in a slightly larger contact patch, and thus more rolling resistance.


> So, offset was adjusted with wheel spacers


I'm not a fan of simply using spacers to push wheels out. I don't think it looks as good as a wider tire.


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## ModFather

garsh said:


> I'm not a fan of simply using spacers to push wheels out. I don't think it looks as good as a wider tire.


I agree, plus you don't get that "deep dish" look of the rim with a different offset. But life is full of compromises, and I am willing to look only "50% cool" if I can get better range.


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## Mad Hungarian

garsh said:


> I'd guess that #1 & #3 had minimal effects.
> #2 is huge, because all else being equal, a wider tire has more rolling resistance.
> 
> I think there are two other large factors affecting efficiency:
> 4. The larger wheels & tires are much *heavier* than OEM.
> 5. The OEM tires were LRR - the new tires are *not LRR*.
> 
> And another small factor:
> 6. I went with a slightly larger-diameter tire than stock in the rear (235/50R17 vs OEM sizes of 215/50R17 or 205/55R16).
> This will result in a slightly larger contact patch, and thus more rolling resistance.
> I'm not a fan of simply using spacers to push wheels out. I don't think it looks as good as a wider tire.


Glad you added points 4 and 5, I totally agree that both would be major factors in your case. I'm not in a position to follow up much today on the rest of the discussion, but I will quickly add one more point that changing tire size actually does not dramatically change total area of the contact patch, what it does is change the shape. Assuming we keep the same air pressure and overall diamter, making the tire narrower will make the contact patch narrower but will also make it longer. Conversely making the tire wider will make the contact patch wider but shorter. In terms of efficiency narrower usually wins because it will lower air resistance (assuming that we're comparing tires with the same rolling resistance qualities).

In a related matter, I'm currently running some tests on my 2013 Volt between the factory 215/55R17 Goodyear Assurance tires on the OE 17x7 forged Aero wheels vs. some 235/45R18 Continental PureContact tires on our Fast FC04 race wheels. Both tires feature strong LRR qualities, and the total assembly weights for both setups are within 1 pound of each other, so it'll be verrrry interesting to see what happens. Since my test loop is 93% steady-speed highway driving and the 18" FC04 is a very open design, I will also try testing those with some improvised flat aero discs to see how much that improves things (@Thomas Mikl this one's for you ).
18" "open" tests are done. 17" OE tests start tomorrow, followed by 18" with aero discs.
I'll start a new thread to discuss results, but will post news of it here when ready.


----------



## ModFather

Mad Hungarian said:


> Both tires feature strong LRR qualities, and the total assembly weights for both setups are within 1 pound of each other, so it'll be verrrry interesting to see what happens. Since my test loop is 93% steady-speed highway driving and the 18" FC04 is a very open design, I will also try testing those with some improvised flat aero discs to see how much that improves things................
> 18" "open" tests are done. 17" OE tests start tomorrow, followed by 18" with aero discs.
> I'll start a new thread to discuss results, but will post news of it here when ready.


VERY interesting. Looking forward to the methodology and results. Would you please include pictures of the three setups in your review. Gracias.


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## Thomas Mikl

What bothers me a lot is that most aftermarket alloys are only designed for looks, very few for weight (costly) and almost none for aerodynamics.


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## Mad Hungarian

Thomas Mikl said:


> What bothers me a lot is that most aftermarket alloys are only designed for looks, very few for weight (costly) and almost none for aerodynamics.


Yes, this is indeed very true. The reason for it though is that until now the market for wheels that optimize aero efficiency above all else is microscopically small. The only folks that care about it are ICE/Hybrid hyper-milers and fanatical EV'ers looking to squeeze that last few kms out of a charge. And since many of the vehicles they drive already come equipped with relatively light, aerodynamic wheels it's hard to convince them to spend money to change. Making new molds costs a lot of money, and we in this biz need to be assured of at least decent sales potential to justify it.
Having said all that I think we're finally going to see some movement on this front. With the hundreds of thousands of Model 3's soon to hit the road (eventually millions... imagine), then the Y, then all the me-toos coming from the slowly awakening competitors I think we'll finally going to reach the critical mass where wheel manufacturers will start offering some nicely designed eco-optimized wheels. I shall say no more...


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## ModFather

Mad Hungarian said:


> I think we'll finally going to reach the critical mass where wheel manufacturers will start offering some nicely designed eco-optimized wheels. I shall say no more...


And the primary market is going to be Ca. So what we need is manufacturing in Ca to cut down on transportation costs. A word to the wise.


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## MichelT3

[QUOTE


TrevP said:


> Michelin Primacy green Acoustic tires in use on the white RC. Runs consistent with Tesla using Contis with foam inserts to reduce tire noise.





TrevP said:


> Michelin Primacy green Acoustic tires in use on the white RC. Runs consistent with Tesla using Contis with foam inserts to reduce tire noise.


These are really growing on me. I actually start to like them. They kind of promote the long range of the car.

Am I wrong in thinking that they are grey alloys with large black plastic lug covers going all the way to the rim, who are fixed by a central nut?


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## ModFather

MichelT3 said:


> [QUOTEThese are really growing on me. I actually start to like them. They kind of promote the long range of the car.


HAH! Take that @Michael Russo !



> Am I wrong in thinking that they are grey alloys with large black plastic lug covers going all the way to the rim, who are fixed by a central nut?


That possibility is gaining traction since the V-spoke wheels have not been seen in a while. Perhaps the V-spokes did not make the final production cut.


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## Mad Hungarian

ModFather said:


> VERY interesting. Looking forward to the methodology and results. Would you please include pictures of the three setups in your review. Gracias.


Will do!


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## Michael Russo

Panda said:


> Dear wheel experts,
> I'm trying to decide between the 18 vs 19 (...)


Dear wheel experts... I am trying to decide between the 18 vs 19... in order to make sure they don't ruin the overall sleek aesthetics of the car... 
Oh, wait... that only leaves me with the 19'' turbines...?!


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## orcinus

18 = range. I like the looks, but i think i like range more


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## Michael Russo

ModFather said:


> HAH! Take that @Michael Russo !(...)


I decided to show a pic of the UWCs to my wife - in a brief moment of insanity... or maybe because I have the audacity to believe I know her taste (ok, maybe this means the same...!) - and her immediate response was 'they look ugly as sin... you don't like them I hope?...' which she followed by 'I'm glad you concur' when I responded to her that 'no, of course, darling'...

So, @Rick59 , I have a new meaning for the by now infamous UWC acronym: 'Ugly, as Wifey-Censored' !!!


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## ahagge

Mad Hungarian said:


> Having said all that I think we're finally going to see some movement on this front. With the hundreds of thousands of Model 3's soon to hit the road (eventually millions... imagine), then the Y, then all the me-toos coming from the slowly awakening competitors I think we'll finally going to reach the critical mass where wheel manufacturers will start offering some nicely designed eco-optimized wheels. I shall say no more...


@Mad Hungarian - Now that we know what the choices will be (and the price on the 19" wheels), I'm hoping that you'll keep us informed of the aftermarket wheel options that become available for the Model 3 as you hear about them. I certainly _hope_ that we can get a better looking set of 18" or 19" rims for less than $1,500...


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## Gizmo

garsh said:


> That red dot on the tire is supposed to be lined up with the valve stem when mounting the tire.
> Bad Tesla Service Technician! Bad!





Mad Hungarian said:


> LOL!
> Actually we might not have to scold said tech, the red dot is the tire's "high point" indicator, which is supposed to be matched to the wheel's lowest point to make for an assembly with the best possible uniformity (closest to perfectly round, in non-tire jargon). Some tires also have a yellow dot that indicates the lightest point of the tire, and that would be the one that should be aligned with the valve stem, which is usually the heaviest point of the wheel.
> Yokohama has a good little tech piece on this here.
> The general consensus is if you have markings that show the tire's high point and the wheel's low point, then that takes precedence over the weight match method (which can be more easily be corrected with balance weights). If not, then yellow-dot-to-valve. Strangely I _have _seen some journal articles that recommend putting the red dot to the valve, even while acknowledging that it's the uniformity marker, but without any further explanation. Manufacturer documents pretty much all agree with the one from Yoko.
> Now the dots are nice, but I far prefer relying on balancers that either use optical or road-force measurement to check what the wheel/tire assembly is REALLY doing. No guesswork and if anything is out of whack these machines will tell you how to re-position the tire on the rim for the best possible result.


Don't forget that with use of WOT the tyres actually rotate on the rims, 
I was sceptical of this until we tried it... place a chalk line on the sidewall where the valve is, then go and do some 'ludicrous' type of driving, you will see the tyre has rotated slightly.

So whilst the dots may be useful for 'normal' driving, once you decide to 'press on' a bit they are less important.


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## KennethK

@Mad Hungarian , now that we know the price of the 18 and 19 wheel options and the tires included with each, here is a scenario for you. Since I live in Michigan and get quite a bit of snow, would it be better to get the 18s and use the tires for a while and later replace with snow tires and purchase a nice set of wheels and UHP all seasons for the rest of the year, or do the opposite and purchase the 19s and buy a set of snow tires /wheels? I do like the looks of the 19s but I do like some ride comfort. I'm not thrilled with the 18s but know I can remove the covers and possibly replace with aftermarket covers.


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## Mad Hungarian

KennethK said:


> @Mad Hungarian , now that we know the price of the 18 and 19 wheel options and the tires included with each, here is a scenario for you. Since I live in Michigan and get quite a bit of snow, would it be better to get the 18s and use the tires for a while and later replace with snow tires and purchase a nice set of wheels and UHP all seasons for the rest of the year, or do the opposite and purchase the 19s and buy a set of snow tires /wheels? I do like the looks of the 19s but I do like some ride comfort. I'm not thrilled with the 18s but know I can remove the covers and possibly replace with aftermarket covers.


Interesting question, and one I'm sure we in snow country are all going to struggle with.
Let's first look at what the sitch is for each season:

*Winter*
1. You are in snow country. You really should have two dedicated sets of wheels and tires.
2. The best winter traction is always achieved with the smallest diameter wheel and tallest/narrowest tire that suits the vehicle
3. We do not know for sure in 17" will fit the M3 (after much study of rears calipers I have my doubts, but still TBA) but we obviously know 18" does so we'll stick with that as THE size.

*Summer*
1. Most would agree that the 19" OE looks nicer, same would apply to most aftermarket choices.
2. 19" will handle better.
3. 19" will be a firmer ride, but with a well sorted multilink suspension as this car has it doesn't have to be spine-rattling deal breaker. For such a young company Tesla are wizards at this.
4. 19" will eat range. We don't know how much yet.
5. 18" OE with Aero covers will give best range, likely of just about anything you'll be able to buy anywhere.
6. 18" with covers removed actually look nice, aftermarket is almost CERTAINLY going to have cap options for this, making the 18" OE an interesting dual-purpose setup.

My rule is start with what's above to see what you want in a perfect world, then move on to Phase Two below, costs, and see if it sways your decision.

*Costs
Configure with 18" and get second set of 18" wheels and winter tires - $1500*
This is the cheapest way out. A nice quality set of aftermarket 18" wheels and tires with TPMS goes for around $1500 in the U.S. (this is a an average figure, YMMV). Now whether you decide to use the OE Tesla 18" wheels for summer or winter is up to you, but I'd likely make them the summer set as this is when you'd most likely travel and those Aero covers will help on the long Interstate hauls.
*Configure with 18", get 18" winter tires and second set of 19" wheels and summer tires - $2300*
An interesting middle-ground choice and the one I'll likely go with. Use the 18" OE wheels for winter and get a nice aftermarket summer set. I allow an estimated value of $2000 for the 19" summer wheel/tire set with TPMS, then add about $600 for a set of 18" winter tires but then deduct $300 for what you'd likely get back on eBay or such for the OE 18" Michelin all-season tires. Again, figures very approximate but are a good average.
*Configure with 19",* *get second set of 18" wheels and winter tires - $3000*
Math here is simple. $1500 for 19" OE option + $1500 for complete 18" winter wheel/tire set with TPMS. Done.

Note that other choices/variables will soon be introduced, such as folks who want to flip their 18" or 19" OE wheels, so there may be deals to be had there are more cars get delivered.
It will also be fun to see what all the different aftermarket combinations look like, of which there will no doubt be TONS (we're certainly going to do our part ). I would in fact not be the least bit surprised if the first private owners get offered significant money to have their cars used at this year's SEMA show in late October to show off the latest in automotive footwear. You can bet I will be on the lookout!

*
*


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## Mad Hungarian

ahagge said:


> @Mad Hungarian - Now that we know what the choices will be (and the price on the 19" wheels), I'm hoping that you'll keep us informed of the aftermarket wheel options that become available for the Model 3 as you hear about them. I certainly _hope_ that we can get a better looking set of 18" or 19" rims for less than $1,500...


Sorry to be late to the party @ahagge , been a crazy week. Why do work and illness always converge when there's major Model 3 stuff going on? The universe has a nasty sense of humour.
I think my reply to @KennethK sort of covers this in a roundabout fashion, but to be more precise there will absolutely be tons of wheel choices for this car, even more than I originally suspected as the weights are far below what everyone estimated. I was _shocked _when I saw even the Long Range model was just a tick over 3800 lbs empty. We still don't know what the Gross Axle Weight Ratings are (please someone get a pic of that placard on the lower door post the next time you see an open driver's door!) but if I scale it up based on most cars of this size/weight there'a a good chance we might be able to use standard load-rated wheels, not the heavy-duty stuff the S and X require.
That will dramatically open up the choices. Still waiting on PCD (bolt pattern) and offset to say for sure what will work, but I have money on them being very similar to S and X, if so there will be lots of off-the-shelf solutions. Pricing of course varies tremendously, in America, land of unlimited consumer choice, you can find decent 19" cast wheels for $150 ea. or sometimes even less. You can of course also go full-on bonkers and blow $1500+ per corner on a gorgeous fully-forged set.
But $1000 should buy you a great set of reasonably light, high quality cast or flow-formed 19" wheels.


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## KennethK

@Mad Hungarian , thanks for the update, I'll have to digest all of it. On a different topic did you see all the pictures of the underbody and suspension components on the shared google photos? They might be of interest to you.


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## MichelT3

I think I might get 2 sets of 18" Tesla wheels with Aero covers, for winter and summer tires.


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## skygraff

So, obviously, best choice is two sets of tires but what's your take on an all-weather (Nokian) in situations where true winter driving is minimal but not uncommon and slush/rain is likely during most of those months?

I live in Chicago so we've been known to get heavy snow but the streets are typically cleared and left slushy (except for a few parking spaces) and I typically take public transport to work.

Even though I like a quiet ride, my current car is a '94 Acura Integra (FWD and 14") so I figure, if I don't get used to the factory set, I will still be pleased with the quieter ride in the Model 3 even with the Nokians. It would be nice if they'd offer a foam lined tire. I may drive the Michelin all-seasons until they need to be replaced and see how I deal with them through winter.

Elon said the RWD Model 3 would be great with all-weathers but he decided not to offer them or work with a manufacturer to set up a quiet variant as a recommended replacement.

Thanks for the breakdown.


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## Gizmo

Can’t comment on all weather Nokian’s but I have used several of their pure winter tyres (WR A4, WR D4, plus another I forget the name of) and they are very impressive.

Even ran then during the summer whist getting summer wheels refurbished without any adverse effect on wear or handling.


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## MichelT3

Winter tires are useful below 7 degrees Celsius. Giving more grip and comfort. It's a huge mistake to think winter tires are only needed for snow.


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## Michael Russo

MichelT3 said:


> Winter tires are useful below 7 degrees Celsius. Giving more grip and comfort. It's a huge mistake to think winter tires are only needed for snow.


For Chicago, there is little doubt in my mind that true winter tires are the way to go.
For me, 'all weather' tires should not be called that way. They're probably not optimal for the summer and not good enough for true winter conditions: the perfect example of a baaaad compromise, IMHO...


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## orcinus

Mad Hungarian said:


> 1. You are in snow country. You really should have two dedicated sets of wheels and tires.


What if you're in bat country?



http://imgur.com/8ISzcR4


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## skygraff

Michael Russo said:


> For Chicago, there is little doubt in my mind that true winter tires are the way to go.
> For me, 'all weather' tires should not be called that way. They're probably not optimal for the summer and not good enough for true winter conditions: the perfect example of a baaaad compromise, IMHO...


Thanks for that insight. I tend to agree with the notion that jacks of all trades are masters of none yet they can be useful when conditions and scenarios are fluctuating rapidly.

With recent Chicago winters, I think the compromise may be better than alternating tires. We have had a few rare "winter" days, a lot of middling days (slush/rain), and more than our share of over 7c (upwards of 26 in February even) days with little transitional time between in order to swap out tires. Mind you, this is from the perspective of somebody who travels for a living so I miss some of the worst, best, and transitional periods. Based on what I've read, aside from them being slightly noisier and shorter lived than all-seasons, it certainly seems like all-weathers may be the right call for Chicago and my driving trends.

I've always felt safe and comfortable with all-seasons in a low FWD car but this'll be the first RWD since my parents had a Mitsubishi mini-van when I was 16. Considering the contrastedly low, heavy, and balanced Model 3 will certainly perform better than that (mid-engine) mini-van in all conditions, I'm probably making too much of this but, if the all-seasons don't work for me, I will probably try the all-weathers before committing to swapping winter tires seasonally (daily?). Or, maybe, use all-weathers as winter tires knowing they aren't ideal for the harshest conditions.

If there's anyone with direct experience, one way or the other, with all-weathers or anyone who can back up (or refute) Mr. Russo's advice with data, it would be appreciated.

Thanks again!


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## Thomas Mikl

Below 7°C which is 44°F a winter tire might save your life in slush/rainy conditions.
Good winter tires have a totally different rubber mix and hence increase grip even on a dry road below that temperature, while an all season will only be bad. All seasons are actually summer tires with a little more profile, which makes them bad in winter as the rubber is too hard and bad in summer as the profile is too steep for pouring rain. IMHO they should be banned from sale.
Any professional driver and test drivers I spoke to always said that their number 1 rule with cars is: NEVER cheapen out on good tires, summer and winter and unless you live in region with zero chance of ever hitting below 50°F you need winter tries.


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## skygraff

Thomas Mikl said:


> Below 7°C which is 44°F a winter tire might save your life in slush/rainy conditions.
> Good winter tires have a totally different rubber mix and hence increase grip even on a dry road below that temperature, while an all season will only be bad. All seasons are actually summer tires with a little more profile, which makes them bad in winter as the rubber is too hard and bad in summer as the profile is too steep for pouring rain. IMHO they should be banned from sale.
> Any professional driver and test drivers I spoke to always said that their number 1 rule with cars is: NEVER cheapen out on good tires, summer and winter and unless you live in region with zero chance of ever hitting below 50°F you need winter tries.


Generally speaking, you are correct but there is a difference between all-season and all-weather.

All-weather is formulated for above and below 7 degrees. They're a compromise, perhaps best used when conditions are variable, but they're not cheap since they're generally premium priced and they don't last as long (due to the softer rubber) as all-seasons let alone alternating between winter and summer tires.

Again, appreciate the time honored wisdom and sorry for hijacking this thread.


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## MichelT3

Living in the eastern part of The Netherlands, where temperatures tend to be below 7 C (44 F) between mid December and end March I use winter tires on separate wheels. The only extra cost is a set of extra wheels, because the summer tires last longer. It gives me much more safety on the road. And I totally agree with @Thomas Mikl; never buy cheap tires. They may cost you your life.


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## JWardell

As posted by @MelindaV in the beta watch thread, this video shows the Model 3 winter testing, on what looks to be stock all-season tires. I think we will all be in for a surprise when it comes to the traction control capabilities of this car.


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## Michael Russo

JWardell said:


> As posted by @MelindaV in the beta watch thread, this video shows the Model 3 winter testing, on what looks to be stock all-season tires. I think we will all be in for a surprise when it comes to the traction control capabilities of this car.


That may very well be... Nevertheless, though I don't own any shares in tire makers...  I will continue to promote the benefits of true snow (or winter) tires for anyone who lives in climates with temperatures under 40-45 deg.F/7 deg.C during parts of the year... And remember, while you have them on your car, you don't incur wear on your 'normal' (summer or 'all-season') tires!!


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## BobLoblaw

I've run 2 sets of the Nokian WRs, they are better than an all-season for sure, not quite as good as a decent full blown winter tire. I would take them over cheap winters. On a side note, at one time (a few years back) the Edmonton RCMP were running them on their police cruisers, at least that's what I heard. Anyone who has spent time in Edmonton knows that's a pretty good endorsement. Myself I used them on our 2009 Jetta TDi for 6 years, went through 2 sets commuting the Coquihalla Highway from Kelowna to Vancouver B.C. 2-4 times a month. Those who know this highway know that it's famous for some pretty nasty conditions (high elevation, mountain passes, it's actually pretty stunning). They performed adequately, can't say they ever scared me, but they definitely didn't excel like a true winter in true winter conditions. 

If you live somewhere that real winter happens, I wholeheartedly recommend a set of winters, or at the very least a set of tires that are "winter rated" and have been certified as such (like the WRs). Plain old all-seasons, especially the high performance variety, suck for the most part in snow and ice. I'll be getting a separate set of rims and tires and running the best winters I can afford, followed by the best all-seasons I can afford once the stockers wear out. Good tires are worth it!


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