# Manual instructions about towing with a Y



## canadian.bacon

Waiting for Y. In the meantime, reading the manual.
Stumbled upon this, can anybody explain to me why I need to mess with the tire pressure every time I tow?
Never had to do this with any other SUV or truck we had.
What is the default tire pressure on a Y? I am expecting the very common 32psi...

https://www.tesla.com/ownersmanual/modely/en_us/GUID-F5C80FF5-8DE3-4750-8BAF-0DCC0CFA0C5C.html

*Tire Pressures when Towing*
When towing a trailer, tire pressures must be adjusted to accommodate the additional load. 19", 20", and 21" tires are acceptable to use for towing. Keep tires inflated to the pressures shown below (if different, these pressures override the pressures that are provided on the Tire and Loading Information Label (see Vehicle Loading)).

Front TiresRear TiresCold Tire Inflation Pressure255/45R19255/45R1942 psi (290 kPa)


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## TrevP

It’s an EV, things are different. Efficiency is paramount so unless you follow their instructions your range while towing will suffer even more than it already does. When towing with an EV expect your range to drop 50% , it’s way more noticeable than a gas car


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## iChris93

It’s always 42 psi. Never 32 psi. Manual should state this too.


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## FRC

Recommended tire pressures are higher on our Teslas, whether towing or not. Both our model 3 and model Y recommend 42 psi all the time.


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## iChris93

FRC said:


> Recommended tire pressures are higher on our Teslas, whether towing or not. Both our model 3 and model Y recommend 42 psi all the time.


Does the door card on your 3 show 45 psi? That was the original recommendation.


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## FRC

iChris93 said:


> Does the door card on your 3 show 45 psi? That was the original recommendation.


Door card on 2018 M3 18's and 2021 MY 19's both show 42. Although I generally run 45 in both.


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## iChris93

FRC said:


> Door card on 2018 M3 18's and 2021 MY 19's both show 42. Although I generally run 45 in both.


My 18 3 shows 45 and haven't checked 22 Y but assume it's 42 as well.


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## FRC

iChris93 said:


> My 18 3 shows 45 and haven't checked 22 Y but assume it's 42 as well.


Yeah, I vaguely recall some back and forth about tire pressures back in 2018 on the 3. I guess they've settled on 42 psi universally, including when towing with a Y.


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## android04

iChris93 said:


> My 18 3 shows 45 and haven't checked 22 Y but assume it's 42 as well.


My early 2018 Model 3 originally showed 45 PSI on the door sticker, but it must have been switched out on a service center visit after Tesla's recommendation changed to 42 PSI. It now shows 42 PSI. Has your 2018 been to the service center any time since the change in recommendation?


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## iChris93

android04 said:


> My early 2018 Model 3 originally showed 45 PSI on the door sticker, but it must have been switched out on a service center visit after Tesla's recommendation changed to 42 PSI. It now shows 42 PSI. Has your 2018 been to the service center any time since the change in recommendation?


Yes, at least twice. Just checked again. Both stickers show 45 psi.


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## canadian.bacon

iChris93 said:


> It's always 42 psi. Never 32 psi. Manual should state this too.


This makes more sense. The recommended tire pressure is 42psi (interesting compared to any other ice I had). I thought I had to screw around with the pressure from 32 to 42 all the time.


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## Rick Steinwand

canadian.bacon said:


> Waiting for Y. In the meantime, reading the manual.
> Stumbled upon this, can anybody explain to me why I need to mess with the tire pressure every time I tow?
> Never had to do this with any other SUV or truck we had.
> What is the default tire pressure on a Y? I am expecting the very common 32psi...
> 
> https://www.tesla.com/ownersmanual/modely/en_us/GUID-F5C80FF5-8DE3-4750-8BAF-0DCC0CFA0C5C.html
> 
> *Tire Pressures when Towing*
> When towing a trailer, tire pressures must be adjusted to accommodate the additional load. 19", 20", and 21" tires are acceptable to use for towing. Keep tires inflated to the pressures shown below (if different, these pressures override the pressures that are provided on the Tire and Loading Information Label (see Vehicle Loading)).
> 
> Front TiresRear TiresCold Tire Inflation Pressure255/45R19255/45R1942 psi (290 kPa)


Because EV's weigh close to 2 tons and for efficiency reasons, they need more air pressure in the tires.

I run 45 psi year round. That was the original tire pressure recommended when I bought my '18 3 and I see no reason to change it.


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## canadian.bacon

Rick Steinwand said:


> Because EV's weigh close to 2 tons and for efficiency reasons, they need more air pressure in the tires.
> 
> I run 45 psi year round. That was the original tire pressure recommended when I bought my '18 3 and I see no reason to change it.


Yes, i understand that. I thought it was normal 32 psi like any other car out there and then you had t bump it to 42 psi when towing, which would have been a drag since we will be going camping every weekend.


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## iChris93

canadian.bacon said:


> Yes, i understand that. I thought it was normal 32 psi like any other car out there and then you had t bump it to 42 psi when towing, which would have been a drag since we will be going camping every weekend.


What camper do you have? Will be interested in hearing your experience.


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## TrevP

I've run 48-49 PSI on my Model 3 without any issues. @Mad Hungarian made me do it 😜


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## FRC

TrevP said:


> I've run 48-49 PSI on my Model 3 without any issues. @Mad Hungarian made me do it 😜


What's the reasoning? I would think your gaining minimal efficiency in exchange for loss of traction, ride comfort, and tire wear.


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## canadian.bacon

iChris93 said:


> What camper do you have? Will be interested in hearing your experience.


6'x12' vnose 6' tall with 15" tires, full aluminum, 1169lb empty. It's an enclosed trailer that we are converting to a camper - we will get a few shelves, a 4' table with 2 chairs, a queen size bed; installed a full RV door with net/lock and window and 2 15"x30" vertical windows on the other side. Rear ramp door with 2 jacks in the corners. Will add 15amp power receptacle to the side for electric campsites, otherwise I have 2 GoLabs 300w with 100w mobile solar panels. Led lights inside, BT speaker and looking at an awning option now. When camping alone or me and one dog, it will the Y only. When the woman comes along, it's the two of us and the 2 dogs, obviously the Y cant handle it comfortably. Currently we camping in the 4runner.


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## garsh

FRC said:


> What's the reasoning? I would think your gaining minimal efficiency in exchange for loss of traction, ride comfort, and tire wear.


I keep mine around 46-47 psi. Mostly because it gives me a better chance of avoiding wheel damage if I end up hitting a bad pothole.
@Mad Hungarian , can you give your reasoning?


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## Mad Hungarian

Wow, a LOT going on in this thread.
Let's do a little review on the whole load capacity vs inflation thing that will hopefully help answer the OP's original questions as well as address some of the follow-up posts.

Every DOT approved road tire sold in North America has to have markings that indicate its maximum load carrying capacity and the maximum permitted cold pressure. However what's missing on the sidewall markings is the pressure at which the tire's load capacity maxes out, which in the case of many models is lower than the maximum permitted pressure.
The standards which govern this for passenger car tires as follows:


Sizing SystemTire Load RangeLoad PressureP-metric (e.g. P255/45R19)Light Load
Standard Load
Extra Load35 psi
35 psi
41 psiEuro-metric (e.g. 255/45R19)Standard
Reinforced or Extra Load (XL)36 psi
42 psi

So if you have a Euro-metric XL 255/45R19, the tire's load carrying capabilities will top out at 42 PSI, at which point it can carry 1,984 lbs. In the specific case of the 19" OE Contis on the Model Y, the rated maximum pressure is 51 PSI, so you can inflate it past 42 right up to that limit but it won't carry more load, it'll just handle differently and use less energy in exchange for (because there is seldom any free lunch in physics) a loss of traction, harsher ride and a little more wear in the center of the tread.

Ideally you want to set the inflation pressure to carry the actual load that's going to sit on it, and that means looking at the load vs inflation table for the tire in question.
For a 255/45R19, the standard and XL versions are below:










So is 42 PSI even necessary to carry a fully loaded Model Y?
Let's look at the Gross Axle Weight Ratings (GAWR):










As we can see, the heaviest demand is on the rear axle at 3606 lbs, or 1803 lbs per tire.
If we look at the load chart for the OE 255/45R19 XL tire above we see that this is already exceeded by the time we hit 38 PSI.

In the case of a Model 3 LR, the spread between what's needed and what's recommended is even greater...



















We can see that in this case the 1385.5 lbs each rear tire needs to handle the car's max legal load on its rear axle is already exceeded at just 35 PSI.
So what's going on?

In order for a tire to perform optimally you want to match the inflation pressure of the tire so that it not only can safely handle the max weight it is expected to carry but also handle, ride and wear properly.
In most cases OEMs will wind up specifying a pressure quite a bit lower than the maximum load carrying pressure because the tire selected for the vehicle is usually rated to carry a maximum weight quite a bit higher than the max of vehicle. They then usually add few more PSI for safety margin (because they know full well how good the average driver is about checking pressures) and then after extensive testing tweak it further to get the exact ride/handling/efficiency result they want. In my experience it usually winds up being anywhere from 10% to 20% above what is strictly required for the weight.

What's interesting in Tesla's case is that virtually all their current models ask for the same pressure, the 42 PSI max load point of the Euro-metric XL chart, regardless of model, trim or GAWRs, which vary quite substantially. I mean I know Elon is a huge Hitchhikers' Guide fan, but is 42 really the answer to everything? This is a uniquely Tesla phenomenon.
A more realistic explanation is that the number one goal is range, range, range, so much so that for a brief period of time (as mentioned in the replies here) Model 3 with 18" did come with a recommended pressure placard showing 45 PSI...










There were a LOT of complaints about ride harshness though, and if I recall correctly excessive wear on the center of the tire (considering they were inflated some 30% beyond what's required for max rear axle that isn't surprising) so they promptly went back to 42 PSI, and many vehicles that had the 45 PSI placard got re-placarded when they went in for service.

Now since many of us are range/efficiency fanatics, we've been known to pump things up on occasion, and for some it's also a way to help mitigate pothole damage as a higher pressure will help reduce the chance the tire will "bottom-out" on impact and allow the rim to come into contact with the edge of a nasty hole or other object in the road. As long as you're willing to live with the increased center wear, ride harshness and slight loss of traction it's not a big deal. But if you don't need any of those features I'd stick with the placard pressure as it does make the car nicer to drive as well as increase both traction and tire life, and as we've seen offers plenty of load carrying capability.

Now, as for towing? Since we've already established that every version of Model Y and Model 3 have inflation pressures that max out their tires' load carrying capacities, I'm not sure I see the point increasing it to tow, especially since the maximum allowable tongue weight of the the trailer is always factored into the GAWR for every vehicle. Tesla would seem to concur, because if we look at their special pressure for towing chart it in every size it recommends - wait for it -

42

Now... if Tesla or any other OEM actually had a different pressure on the placard or in the manual depending on the actual load case, it's a different story, you need to adjust to follow suit. This is very common in the European market where they believe owners are intelligent enough to actually monitor and change pressures based on how the vehicle is being used. However here in North America we can't even be trusted to check our pressures even once a year (which is mostly why we now have TPMS, but that's a much longer story), which is too bad 'cause I really like that EU inflate-for-use system.

At the end of the day that means the pressure on the door placard in virtually every passenger vehicle sold here is designed to really be a worst-case scenario, and that includes towing.
So unless you have exceptionally bad roads or you're trying to set an efficiency record just stick with the sticker pressure and you'll be fine.


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## Mad Hungarian

TrevP said:


> I've run 48-49 PSI on my Model 3 without any issues. @Mad Hungarian made me do it 😜


For the record, I did not.
I just told him he wouldn't die if he did.
#FakeNews


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## FRC

Mad Hungarian said:


> For the record, I did not.
> I just told him he wouldn't die if he did.
> #FakeNews


So, at 48-49 PSI, I'll live forever??


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## canadian.bacon

I do check my tire pressure regularly since it is on the dashboard. I will stick with the 42 psi, those engineers gotta know more than we do.


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## Mad Hungarian

FRC said:


> So, at 48-49 PSI, I'll live forever??


No, just Trev.
He's actually a vampire.
(all those random Tweets between midnight and 5:00 am? C'mon...)


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## canadian.bacon

@Mad Hungarian 
Thanks for all the info in this thread. New to EVs, new to Tesla, so I have to move away from the traditional ways of doing things. A bit of an off topic about towing, but still on tires 

Is this still valid? https://teslaownersonline.com/threads/model-y-winter-package.16977/post-296712
I only need to buy a set of TMPS sensors from Tesla for my winter rims, get them installed and that is it? No issues switching the tires/rims twice a year?


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## Mad Hungarian

canadian.bacon said:


> @Mad Hungarian
> Thanks for all the info in this thread. New to EVs, new to Tesla, so I have to move away from the traditional ways of doing things. A bit of an off topic about towing, but still on tires
> 
> Is this still valid? https://teslaownersonline.com/threads/model-y-winter-package.16977/post-296712
> I only need to buy a set of TMPS sensors from Tesla for my winter rims, get them installed and that is it? No issues switching the tires/rims twice a year?


Yes indeed, the new gen Bluetooth sensors are auto-learning just like the old ones, so easy-peasy when switching back and forth from summer to winter sets.


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## canadian.bacon

@Mad Hungarian 
cool stuff, trying to get the knowledge in before the Y gets delivered. 
Also weary about 18" rims and tires for the winter, will stick to factory defaults, unless something REALLY changed and the 18" are awesome and Tesla has no issues with it.


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