# Model 3 on the snow - so far, so ok



## PatrickM

One of the big questions is the RWD now vs. wait for AWD question. I live in Fort Collins, Colorado and we do not get substantial snow very often, the streets are snow free at least 46 weeks out of the year in a typical year and usually even better than that. Fort Collins (and Denver) are kind of famous for snowstorms that are followed by warm weather so snow usually doesn't last very long.

But on Saturday we had a rare (for us) combo of freezing rain followed by light snowfall and I specifically took the car out early in the morning to see how it did on what was mostly an ice rink with a bit of snow on top, and it did ok. It basically drives better than any RWD drive car that I've personally ever driven, but it still drives like a well-behaved RWD car. On a straight line, the tires would spin a bit, but not too bad. On turns it was a bit squirrelly with a tendency for the rear to fish tail out a bit so I was sliding around a bit - particularly on turns. The traction control seemed pretty solid and I didn't see a way to disable it, not that I would normally want to disable it anyway, The aggressive regen put me into at least one slide at one point early on and so I toned down the regenerative braking in the menu option. But once I got the feel of the car, I was cruising around - slowly - with a minimal amount of trouble, and this was about as bad as it gets in Fort Collins barring a an extremely rare blizzard - freezing rain is nasty stuff.

I don't think I'd take it in the mountains to go skiing in a storm, I intend to buy and carry four sets of chains or cables (RWD you need to do all 4 wheels, not just the rear or front), but I am content with my decision to get RWD now. It was ok in the snow - I slid a bit but once I learned the car, I thought it was ok.

(Edit: changed original post to fix a typo where I meant weeks and typed months)


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## TheTony

What tires are you using?


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## PatrickM

TheTony said:


> What tires are you using?


Yeah, good question. I should have mentioned that. The stock factory tires which are Michelin Primacy MXM4 all-season tires.

These: https://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Primacy+MXM4


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## Wilson

PatrickM said:


> One of the big questions is the RWD now vs. wait for AWD question. I live in Fort Collins, Colorado and we do not really get real snow very often, the streets are snow free at least 46 months out of the year in a typical year and usually even better than that. Fort Collins (and Denver) are kind of famous for snowstorms that are followed by warm weather so snow usually doesn't last very long.
> 
> But on Saturday we had a rare (for us) combo of freezing rain followed by light snowfall and I specifically took the car out early in the morning to see how it did on what was mostly an ice rink with a bit of snow on top, and it did ok. It basically drives better than any RWD drive car that I've personally ever driven, but it still drives like a well-behaved RWD car. On a straight line, the tires would spin a bit, but not too bad. On turns it was a bit squirrelly with a tendency for the rear to fish tail out a bit so I was sliding around a bit - particularly on turns. The traction control seemed pretty solid and I didn't see a way to disable it, not that I would normally want to disable it anyway, The aggressive regen put me into at least one slide at one point early on and so I toned down the regenerative braking in the menu option. But once I got the feel of the car, I was cruising around - slowly - with a minimal amount of trouble, and this was about as bad as it gets in Fort Collins barring a an extremely rare blizzard - freezing rain is nasty stuff.
> 
> I don't think I'd take it in the mountains to go skiing in a storm, I intend to buy and carry four sets of chains or cables (RWD you need to do all 4 wheels, not just the rear or front), but I am content with my decision to get RWD now. It was ok in the snow - I slid a bit but once I learned the car, I thought it was ok.


You have really long years in Fort Collins!
Also thanks for the info.


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## PatrickM

Wilson said:


> You have really long years in Fort Collins!
> Also thanks for the info.


Ack. I've done that twice in the last couple of hours. I sent an email to a big group at work where I mixed days and weeks. Fixed. Thank you..


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## LucyferSam

Here in Iowa we've had solid snow cover on our roads for the last 2 weeks or so (finally melted off the roads yesterday), and while it's definitely taken some getting used to the different handling of the RWD on snow it is slightly more stable than my FWD Camry was (factory Primacy's on the 3, also had Primacy's on the Camry but don't remember which variant). I'll probably get snow tires for next year as I'd prefer a little more stability and after a year of wear the factory tires will be a little worse on the snow, but they have been perfectly usable so far.


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## Michael Russo

PatrickM said:


> Yeah, good question. I should have mentioned that. The stock factory tires which are Michelin Primacy MXM4 all-season tires.
> 
> These: https://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Primacy+MXM4


Wow. Imagine how much better you'd feel with proper winter tires then, Patrick... !


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## NJturtlePower

PatrickM said:


> I intend to buy and carry four sets of chains or cables (RWD you need to do all 4 wheels, not just the rear or front), but I am content with my decision to get RWD now. It was ok in the snow - I slid a bit but once I learned the car, I thought it was ok.


Not correct chain usage according to Tesla who specifically states, "
Note: Chains should only be installed on the rear wheels of the Model 3 and only on 18" tires. The use of non-recommended tire chains has been shown to cause suspension and other vehicle damage."

In my opinion true winter tires will do you better than chains in everything but deep snow, which honestly the Model 3 is not cut out for due to its low ground clearance. Improved traction AND braking is key.

https://shop.tesla.com/us/en/catego...tesla.car.accessories.model.3.m3.wheels.tires


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## Runt8

PatrickM said:


> One of the big questions is the RWD now vs. wait for AWD question. I live in Fort Collins, Colorado and we do not get substantial snow very often, the streets are snow free at least 46 weeks out of the year in a typical year and usually even better than that. Fort Collins (and Denver) are kind of famous for snowstorms that are followed by warm weather so snow usually doesn't last very long.
> 
> But on Saturday we had a rare (for us) combo of freezing rain followed by light snowfall and I specifically took the car out early in the morning to see how it did on what was mostly an ice rink with a bit of snow on top, and it did ok. It basically drives better than any RWD drive car that I've personally ever driven, but it still drives like a well-behaved RWD car. On a straight line, the tires would spin a bit, but not too bad. On turns it was a bit squirrelly with a tendency for the rear to fish tail out a bit so I was sliding around a bit - particularly on turns. The traction control seemed pretty solid and I didn't see a way to disable it, not that I would normally want to disable it anyway, The aggressive regen put me into at least one slide at one point early on and so I toned down the regenerative braking in the menu option. But once I got the feel of the car, I was cruising around - slowly - with a minimal amount of trouble, and this was about as bad as it gets in Fort Collins barring a an extremely rare blizzard - freezing rain is nasty stuff.
> 
> I don't think I'd take it in the mountains to go skiing in a storm, I intend to buy and carry four sets of chains or cables (RWD you need to do all 4 wheels, not just the rear or front), but I am content with my decision to get RWD now. It was ok in the snow - I slid a bit but once I learned the car, I thought it was ok.
> 
> (Edit: changed original post to fix a typo where I meant weeks and typed months)


Great info, thanks! I'm a bit hesitant going with RWD but I've heard Teslas do very well.

Also, I test drove a Model S today, the sales guy mentioned that in the snow you should turn regen braking down to low to prevent slides, guess he actually knows what he's talking about


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## PatrickM

NJturtlePower said:


> Not correct chain usage according to Tesla who specifically states, "
> Note: Chains should only be installed on the rear wheels of the Model 3 and only on 18" tires. The use of non-recommended tire chains has been shown to cause suspension and other vehicle damage."


Wow. Good to know. Thanks for the correction.


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## Karl Fisch

Hi Patrick. Live in Highlands Ranch, just south of Denver, have configured and waiting for VIN and delivery. Have similar thoughts about front-range Colorado winter and roads. Was wondering if since this post you had had a chance to drive in any additional snowy conditions and, if so, how it went and if you're still thinking of going with chains or possibly getting snow tires (or neither).


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## PatrickM

As you know it's been an unusually mild winter so there hasn't been much chance to drive it in any really big storms but the ones that we have had have all been fine. I tell people that it drives a bit like my old Prius except that it slides a bit differently when it does slide. But it seems to me to drive ok - but not great - in a bit of snow. About as well as a typical ICE compact car, but with different handling that takes a bit of getting used to. But we had at least one ice storm about 5 weeks or so ago where we had frozen rain followed by snow and that was a pretty slick night and I saw other cars and pickups sliding around and I just drove slowly and all was fine.

So on the one hand, I don't know what I don't know and we haven't experienced any really big storms since I got the car in Feb. But on the other hand, everything that we have had has been fine... and that's on the stock tires.

A bunch of my co-workers ask me if they should wait for AWD or get RWD for their Model 3 orders and that's a hard thing for me to comment on because I really just wanted my car and so the concept of waiting wasn't going to happen and everyone has different expectations for cars. But I have zero concerns that I personally made the wrong decision - I am always one of those people who would work from home in a storm because my Prius was the opposite of an all-weather vehicle and now I have the same thing with the Model 3 except that I also don't want road grit scratching it.  So my plan is to watch the weather and stay home when the forecast is bad. If you do a lot of winter driving and staying home is not an option when we have one of roughly 5-10 days out of the year when it really storms, then wait for AWD, but if you have an alternate car or can just not drive the Model 3 when it's insane outside, then I think the RWD works pretty well in Colorado and I have no regrets about my decision.


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## Karl Fisch

Thanks, definitely not waiting for AWD, will hopefully get it in 2-4 weeks. Was just wondering stock tires vs. chains vs. switching out to winter tires (which I've never done on previous vehicles, including my 2006 Prius). Think I may just go with stock tires and see how they do through next winter (assuming we have a winter).


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## PatrickM

Karl Fisch said:


> Thanks, definitely not waiting for AWD, will hopefully get it in 2-4 weeks. Was just wondering stock tires vs. chains vs. switching out to winter tires (which I've never done on previous vehicles, including my 2006 Prius). Think I may just go with stock tires and see how they do through next winter (assuming we have a winter).


I hope for the sake of our water supply that we don't have another winter like this one next year. But yeah, that seems like a plan.

I had a plan to buy cables on Amazon and carry them around but I never actually did it.


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## Sabine

Thanks for this info.

I live in Alberta and have winter/snow-covered roads for about 4 - 5 months out of the year, possibly longer. I have NEVER driven a RWD and am seriously hesitating getting one. That said, the US:Canada exchange rate sucks at the moment and I do NOT make 6 figures ... and I absolutely need the extended range, so I'm wondering if I can manage without AWD. 1.5 years ago I hit black ice on the HWY and crashed my vehicle, so I'm extra apprehensive at this point in time (though really, will AWD save me when there's black ice?). Just voicing my consternation as I don't want to drop a whole lot of money only to find out I can't handle the vehicle on icy roads or in deep snow.

Anyone from Canada have any experience to share?

Also, I am currently renting a very small house. I do have access to a (cough) garage (it's crap) which would allow for 110 charging. Does this work on a Model 3? I walk to work, so it'd be used just for grocery shopping and long distance trips to bigger cities. The city I live in does not have a Supercharger.


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## Runt8

Sabine said:


> Thanks for this info.
> 
> I live in Alberta and have winter/snow-covered roads for about 4 - 5 months out of the year, possibly longer. I have NEVER driven a RWD and am seriously hesitating getting one. That said, the US:Canada exchange rate sucks at the moment and I do NOT make 6 figures ... and I absolutely need the extended range, so I'm wondering if I can manage without AWD. 1.5 years ago I hit black ice on the HWY and crashed my vehicle, so I'm extra apprehensive at this point in time (though really, will AWD save me when there's black ice?). Just voicing my consternation as I don't want to drop a whole lot of money only to find out I can't handle the vehicle on icy roads or in deep snow.
> 
> Anyone from Canada have any experience to share?
> 
> Also, I am currently renting a very small house. I do have access to a (cough) garage (it's crap) which would allow for 110 charging. Does this work on a Model 3? I walk to work, so it'd be used just for grocery shopping and long distance trips to bigger cities. The city I live in does not have a Supercharger.


AWD helps you get started, but it does next to nothing to stop you (there are some differences with traction control, but traction control only works if your tires actually have traction). The best thing you can do for any car, RWD, FWD, or AWD, is to use good snow tires in the winter. After seeing all the videos and reading comments about how good RWD Tesla's handle in the snow, I'm not very concerned.

As for 110 charging, you will get somewhere between 3 and 5 miles per hour. You need to figure out how long you will have it plugged in each day vs. the number of miles you drive to determine if it's sufficient for you.


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## garsh

Runt8 said:


> After seeing all the videos and reading comments about how good RWD Tesla's handle in the snow, I'm not very concerned.


And a thread on that topic:

Worried About Snow? Don't Dismiss Getting Rear Wheel Drive!


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## Sabine

Runt8 said:


> AWD helps you get started, but it does next to nothing to stop you (there are some differences with traction control, but traction control only works if your tires actually have traction). The best thing you can do for any car, RWD, FWD, or AWD, is to use good snow tires in the winter. After seeing all the videos and reading comments about how good RWD Tesla's handle in the snow, I'm not very concerned.


Thank you for your reply. I did test drive a couple of RWD SUVs 1.5 years ago, and they handled fairly well on the snow-covered streets despite being top heavy. I'm just sharing the thoughts in my head (I should probably stop doing so) as my biggest fear is, as you said, not being able to get started as I live in an older neighbourhood, on a one-way street, where there isn't much "wiggle room" when the roads are slick and there's lots of snow on the ground. Guess I just better make sure I have good insurance coverage.


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## Archaebald

Sabine said:


> ... though really, will AWD save me when there's black ice?


This is a topic on which there seems to be as many opinions as there are discussants (ping @KarenRei) . Where I live, winter conditions seem to be similar to your (although black ice is not so common, usually we have stable below-zero degrees and compressed snow/rugged ice on the streets). From my experience (i.e., opinion in disguise...) FWD, RWD, or AWD is a matter of which tires you prefer loose traction when driving "agressively"/irresponsibly. Although AWD DOES help you get going, I have never experienced any situation were AWD has been absolutely necessary. Even when driving were I shouldn't, e.g., in DEEP snow where the car eventually ended up resting on the undercarriage rather than the tires, RWD/FWD has been sufficient to get out of the situation (after some digging...) I have found proper winter tires - NOT "all season" - and adjusting your speed to the road conditions to be the A-Z of safe winter drivning, way more important than the type of drivetrain you have. You just have to accept you will not always be the first out of the trafic lights during winter..


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## KarenRei

It's about the difference between static and dynamic friction. Static friction is the force resisting you move at all. Dynamic friction is the force trying to slow you down once you are moving. With tires, you always want to be dealing with static friction; on any given tire, once you pass the limit, you're sliding (the amount of force that will "break" your traction varying depending on your tires and the amount of lateral force being applied to them). This force can come from a number of things - braking, cornering, accelerating, or even simply maintaining speed. Remember that all of that energy you're burning to maintain your speed is going into traction force on your tires, even if you're not accelerating; it's just a much greater amount of force when you are accelerating.

Since there's more force on your drive wheels, they lose grip first. This can happen when accelerating hard, accelerating normally out of a turn, or simply maintaining speed if the road is slippery enough. In a RWD car, if the rear tires lose traction but the front tires maintain it, you fishtail, as the front wheels keep going where they were aimed, but the rear wheels slide out to either side.

With AWD, the lateral force on the tires from braking or cornering remains unchanged, but the force from acceleration or maintaining speed is halved. The odds of having at least one drive tire on a good surface is also doubled. Lastly, if you do lose traction, you're more likely to lose it on both the front and rear, avoiding fishtailing.

I often experiment on my pickup during the winter, which I can switch between AWD and RWD. I'll go around a corner and accelerate on my way out of it (like a person normally does), but at a speed that's deliberately too high for the road conditions. If I'm in RWD, the amount of acceleration needed to lose traction on the rear wheels is a lot less (sometimes, on a really bad road, barely anything), and the truck heavily fishtails. If I'm in AWD, I have to gun it a lot harder to lose traction, and the whole truck slides evenly, just taking the corner wide.

Statistically, AWD vehicles in a given vehicle class usually have lower accident rates in the winter. However, the accidents are often more severe because the speeds are higher. Sadly, a lot of people compensate for their better handling on icy conditions simply by driving faster. It should go without saying, but _don't do this_.  It's like people who respond to having AP by spending their drive fiddling around with their phone.

And it should also go without saying... but AWD is not an excuse to not put winter tires on.


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## verygooddog

KarenRei said:


> And it should also go without saying... but AWD is not an excuse to not put winter tires on.


KarenRei's post gives a very good description of the forces and variables present in icy/snowy conditions. I no longer live where there's snow and ice in the winter, but for most of my life I did.

It's important to remember that braking forces are the same with RWD, FWD and AWD. I've seen so many vehicles with AWD going excessively fast in slippery conditions, most likely because they can accelerate faster than RWD and FWD vehicles and either don't realize or forget that they can't stop any faster. Driving in snowy conditions, it always seems to me that the overwhelming majority of vehicles that have slipped off the road are AWD vehicles. I think that most people who don't have AWD drive much more conservatively in snowy/icy conditions.

For many years I lived in a very snowy rural area, with lots of steep hills, and black ice was very common. The only reliable way for me to safely travel in snow was with winter tires. Winter tires will help a bit in black ice conditions, but, in my opinion, the only sure bet for black ice is to add studs to the tires.


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## Archaebald

verygooddog said:


> Winter tires will help a bit in black ice conditions, but, in my opinion, the only sure bet for black ice is to add studs to the tires.


 Yup, tires with studs is what I meant with "proper winter tires" (Standard over here. Didn't even reflect over the fact it could mean something else... Sorry for my ignorance)


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## KarenRei

Note about studs: if you normally drive in a place where roads are kept clear of ice, they can actually increase your braking distance. They're also a big road wear and pollution problem where I am. We actually have set time periods for them, and if you don't remove your studded tires outside of the winter season you can get ticketed. They also increase road noise.

Don't get me wrong, if you're going to mainly be driving on icy country roads, I definitely recommend them! But if your driving is mostly in town, you might want to think twice.


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## Mesprit87

Same here in Québec, winter tire use is limited. 
As for studs, they could be practical maybe twice a year. 
And they would destroy my epoxy floor


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## Archaebald

KarenRei said:


> Don't get me wrong, if you're going to mainly be driving on icy country roads, I definitely recommend them! But if your driving is mostly in town, you might want to think twice.


I agree completely. Similar rules about the use of studded tyres apply here. As a matter of a fact, in increasingly many areas (usually were they do not have so much snow), studded tires are banned all year around, for the reasons you mentioned. The problems with studded tires are real and should definitely be taken seriously. Luckily, I live in an area were most roads are ice/snowcovered during the winter. I say luckily, not because I like to drive around with studded tires, but because I love snow!


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## Archaebald

Mesprit87 said:


> As for studs, they could be practical maybe twice a year.
> And they would destroy my epoxy floor


Two days? And I who believed you have real weather in Canada... 

You should see the clawmarks on my industry standard ceramic garage floor tiles...


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## DinosM

So everything I read is a bit contradicting, some peeps say 4 wheel drive for winter drive some say nothing can replace winter tires and of course the best solution is 4 wheel drive and winter tires. But if you have to choose, 5K for AWD and wait another 3-4 months or spend 2k to get the winter tires from Tesla and get the car in 2 months. Any advice?


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## Runt8

DinosM said:


> So everything I read is a bit contradicting, some peeps say 4 wheel drive for winter drive some say nothing can replace winter tires and of course the best solution is 4 wheel drive and winter tires. But if you have to choose, 5K for AWD and wait another 3-4 months or spend 2k to get the winter tires from Tesla and get the car in 2 months. Any advice?


Personally I'm getting RWD with winter tires. I spent 12 years driving in Colorado without AWD on all season tires without any problems, so a low center of gravity Tesla with winter tires will be a huge upgrade for me. While AWD would be nice, it's not worth it to wait several more months and potentially miss out of the full tax credit.


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## Archaebald

The only thing I'd strongly advice against is drivning in winter conditions without winter tires (they make a BIG difference). Hence, your AWD option should include winter tires. From my perspective, the rest is a matter of how eager you are to get your car and the thickness of your wallet. Can't help you on any of those, I'm afraid...


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## DinosM

I'm 4/1 online reservation and really do not want to extend my wait. I'm moving from Ohio to Connecticut and I think I will stay with the RWD and get the winter tires. Tesla has a set of winter tires/rims for $2k, that does not seem like a bad price?


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## PNWmisty

KarenRei said:


> Statistically, AWD vehicles in a given vehicle class usually have lower accident rates in the winter.


I was with you 100% before you said this ^^^

In my experience in winter conditions, AWD vehicles are MORE likely to get into accidents. Because human factors are the most important variable and AWD drivers are often over-confident. They also think they don't need winter tires because they have AWD. That's two strikes against them right there.

Do you have a link to support your claim of a lower accident rate of vehicles having AWD?


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## PNWmisty

verygooddog said:


> Winter tires will help a bit in black ice conditions, but, in my opinion, the only sure bet for black ice is to add studs to the tires.


I can tell it's been a number of years since you've bought winter tires. Because they keep getting better on black ice. While studs might have a 20% advantage on black ice compared to the better studless winter radials, this assumes the studs are new. Once they are rounded and worn somewhat, a studless tire with the same number of miles can actually outperform the studded tire. Because studs have poor retention in the type of rubber compounds that are best for winter roads. Some winter tyres can be improved with studs but the best winter tires are not compatible with studs.

Studs had their place in automotive history but are being rendered obsolete by better rubber compounds. Anyone who has not driven the latest crop of studless tires needs to give them another go. The black ice traction is very good, much better than even 10 or 12 years ago.


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## Archaebald

Here are some results from my, totaly unstructured and non-exhaustive, review of the papers I found on google scholar on the topic of AWD versus TWD and winter tires.

Winter tires outperform summer and all-season [sic] tires in temperatures below 45 F, even when roads are not snow covered. "
A two-wheel drive vehicle with winter tires will outperform a fourwheel drive vehicle with all-season tires in braking and cornering. The perception that four-wheel drive vehicles do not require winter tires in cold climates is false."​"More to the point, in terms of crash avoidance, a two-wheel drive vehicle fitted with winter tires will significantly outperform a four-wheel drive vehicle with all-season tires (experiencing approximately 35% shorter braking distance" http://umich.edu/~umtriswt/PDF/SWT-2016-10.pdf

On snowy/icy roads, crashes where drivers or passengers were injured increased by 19-31% for AWD and showed 13-15% higher impact severity. Authors suggested that the main cause for this finding is that AWD masked the slipperiness of the road, hence drivers underestimated the risk of accidents: http://indexsmart.mirasmart.com/25esv/PDFfiles/25ESV-000260.pdf
In addition to the masking effects of AWD, there is some evidence for a tendency of 
AWD drivers to drive more carelessly than TWD drivers. Obviously, this could have contributed to the higher risk of being involved in a severe accident in an AWD, compared to in TWDs: http://www.ijmedph.org/article/238?qt-sidebar_tabs=2
https://www.sciencedirect.com/science/article/abs/pii/S1369847808000168​Finally, studded tires are better than every other type of tire in near zero (C) temperatures on icy/snowy roads, although the difference against studless winter tires decreases as the friction of the surface increases (i.e., with falling temperatures and/or rugged snow/ice): https://www.sciencedirect.com/science/article/abs/pii/S0001457511003083


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## PNWmisty

Archaebald said:


> On snowy/icy roads, crashes where drivers or passengers were injured increased by 19-31% for AWD and showed 13-15% higher impact severity. Authors suggested that the main cause for this finding is that drivers of AWD masked the slipperiness of the road, hence drivers underestimated the risk of accidents: http://indexsmart.mirasmart.com/25esv/PDFfiles/25ESV-000260.pdf


Yes! As a winter sports enthusiast, I drive a lot of miles in severe mountain weather and that matches my unscientific observations very well. Only thing I might add is the ratio of crashed AWD's to the percentage of all AWD's seems a little higher than that study would suggest!



> Finally, studded tires are better than every other type of tire in near zero (C) temperatures on icy/snowy roads, although the difference against studless winter tires decreases as the friction of the surface increases (i.e., with falling temperatures and/or rugged snow/ice): https://www.sciencedirect.com/science/article/abs/pii/S0001457511003083


Every study comparing studded tires to studless winter tires that I've seen has only compared brand new studded tires, before they are rounded off and worn by bare pavement. My real world experiences tell me that the ice performance of studs falls off much, much faster than that of studless. And because studded tires are designed to rely on the studs, the rubber compound used is not as soft as the best studless tires. So, as the two classes of winter tires wear down a bit with usage, the ice performance of studless tires actually passes the performance of studded tires. Yes, they don't work as well as the tests indicate once the studs are worn and it doesn't take too many highway miles on bare or bare/wet pavement to cause the studs to become rounded.

Some studless winter tires are dual compound and their performance on ice decreases dramatically when the winter rubber compound has worn off. I avoid dual compound tires and recommend that others avoid them also (unless you like throwing out your tires at half tread). I buy winter tires that continue working well until 75% of the tread is gone.

As to AWD vs. 2WD, the best AWD setups have a small safety advantage. Most of the older AWD and 4WD technologies are actually LESS SAFE in very low traction situations like black ice. I have driven and owned a large variety of AWD and 4WD vehicles in the snow and many AWD vehicles have become better than they were in the past thanks to quicker and more precise electronics and the resulting faster reacting torque vectoring.

The AWD vs. 2WD debate can become heated with adamant people on both sides of the debate. Some of this difference of opinion originates with people that have driven vehicles that can be switched from 2WD to AWD with the flip of a switch. Here's the deal: An AWD vehicle switched to 2WD is not as good on slippery surfaces as a native 2WD vehicle. That's because of the extra drag and rotational inertia caused by the AWD hardware that is no longer powered (but must still rotate regardless). The power to rotate the extra bearings and shafts comes from the traction of the tires of the remaining two driven wheels. In effect, this additional friction and rotational inertia subtracts from the remaining available traction and makes the initiation of a slide more likely.

Do not judge the effectiveness of AWD vs. 2WD by putting an AWD vehicle into 2WD! It's not remotely close to the same thing, especially on very slippery surfaces.


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## Archaebald

PNWmisty said:


> My real world experiences tell me that the ice performance of studs falls off much, much faster than that of studless. And because studded tires are designed to rely on the studs, the rubber compound used is not as soft as the best studless tires.


I am not in the position to compare studded vs studless tires myself, since I have exclusively used studded tires. Nevertheless, it is also my experience that the studded tires loose some amount of grip after three winter seasons, which corroborates your observations. 
However, at that point of time, the studs usually have not become rounded off to any greater extent (I mostly drive on snowy/icy roads) and the tire pattern does not show any significant signs of wear. Hence, I think most of the loss of grip can be attributed to the rubber compound becoming oxidized/harder, rather than the wear and tear of the studs/tire pattern. My unscientific observations over the decades suggest that this ageing is less pronounced for modern premium studded winter tires, compared to older and/or non-premium ones - in addition to being significantly more silent than before (and, allegedly, causing less road wear). Keeping the tires for three years (i.e., the recommended life span) is no problem as the their performance is still fully acceptable in the third year.
I do not know to what extent, and at what rate, studless tires also suffer from oxidation/hardening, but think that the finding that "Studded tires were found to have a statistically significant effect of 42% in terms of fatal crash reduction on roads covered with ice or snow, compared to non-studded winter tires." [https://www.sciencedirect.com/science/article/abs/pii/S0001457511003083] was a pretty convincing argument for me to stick with studded tires  It is reasonable to assume that studded and studless tires of varying age/wear were represented in this study, so I am not sure the assumption that studless tires catch upp and surpass studded tires holds (however, it would certainly be interesting to see comparisons of subgroups of tires of different age). That said, I do acknowledge that winter conditions differ and that tires that are suitable for me, in the typical winter conditons in my neighbourhood, may not be optimal for someone else.

As to the AWD/4WD /TWD discussion, I think the
 amount of available data is still not sufficient, valid, and reliable enough to​rule out any of those, or put one before the other when it comes to safety in winter conditions. Currently, in my opinion, winter tires, ESC, and a sensible driver still seem to be the most important factors for getting you safely from A to B.


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## PNWmisty

Archaebald said:


> I am not in the position to compare studded vs studless tires myself, since I have exclusively used studded tires. Nevertheless, it is also my experience that the studded tires loose some amount of grip after three winter seasons, which corroborates your observations.
> However, at that point of time, the studs usually have not become rounded off to any greater extent (I mostly drive on snowy/icy roads) and the tire pattern does not show any significant signs of wear. Hence, I think most of the loss of grip can be attributed to the rubber compound becoming oxidized/harder, rather than the wear and tear of the studs/tire pattern.


I think this is an example of different environmental conditions providing different results. If you drive mostly on snowy/icy roads your speeds are probably lower and the predominately snow/ice covered roads reduce the speed at which the studs are abraded and rounded off.

Much of the West Coast has snow-free roads in the lowlands (where people routinely drive 70 mph) and extreme winter conditions above 1000-4000 feet. The high-speed pavement driving wears studs very quickly, especially on concrete and chip-seal surfaces. Couple that with rain (which causes micro-slipping) and the studs take a real beating.

I have had winter tires where the rubber oxidizing/curing caused the ice performance to fall off dramatically after only 2 seasons (I believe they were the first version of Michelin X-Ice if memory serves) but that was a long time ago. My current winter tires completed 5 winter seasons (and amazingly enough one summer of about 2,000 miles) and last winter had not lost any noticeable ice traction. Of course, traction in slush was compromised due to the small amount of tread depth left. They were Goodyear Ultra Grip Ice WRT's. I will note I've had studless tires with a bit more grip on glaze ice but these tires were amazing on bare wet pavement and didn't lose the moderately good ice traction they started with. How much the rubber hardens/cures over time/usage is different for different compounds. The situation has improved a lot in recent years.

Yes, it's important to get tires suited to your particular area and use patterns. But if you haven't tried studless tires in recent years you might be in for a pleasant surprise.


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