How well do 21" winter tires perform in the mountains?

[pschloes]

Have seen various threads indicating 20" winter tires are best for snowy conditions, but looking for experiences with 21." thanks!

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[PrudentOcean]

There should be very little difference, if any. The tire circumference is the same, the only difference is the height of the sidewall due to the different wheel diameters. Tread pattern and tire compound are what makes a difference.

 

[sloubere]

The 20" are better for cold conditions in general due to the battery savings over the 21" tires which is more of a concern for cold temperatures as a cold battery stores less power over a warm battery.

I do not know whether the road handling over snow between 20" and 21" is that different.

 

[LivingTheDream]

One other thing that impacts winter tire performance is tread width. Thought they're great in the summer, wider tires are actually a disadvantage in winter. Narrower tires can better cut through the snow, instead of riding on top of it. For this reason, the 20" wheels can be expected to outperform the 21" wheels—though how much and whether or not you'd notice the difference is not a question I can answer.

Here are the tire specs for the 20" wheels...

• Front: 7.5J x 20 ET32 wheels with 235/55 R20 tires
• Rear: 10J x 20 ET49 wheels with 285/45 R20 tires

Here are the tire specs for the 21" wheels...

• Front: 8.5J x 21 ET27 wheels with 255/45 R21 tires
• Rear: 10.5J x 21 ET47 wheels with 295/40 R21 tires

(data taken from the configurator for the US)

 

[PrudentOcean]

Dedicated winter tires create traction by packing snow into the tread pattern, and that snow will stick to the snow on the ground. So a wider tire can create more traction than a narrower one under those circumstances.

 

[LivingTheDream]

Dedicated winter tires create traction by packing snow into the tread pattern, and that snow will stick to the snow on the ground. So a wider tire can create more traction than a narrower one under those circumstances.

I have never heard that as an explanation for what drives the effectiveness of winter tires, so that’s a new one for me. That said, I’ve read the “narrower is better” thing in several articles on winter tire performance. Did a little online searching and found this…

The “narrower is better “ thesis seems to be the most supported, especially for traction, but the details are complex and don’t unambiguously point us in one direction or the other (see this excellent video). What appears to be unequivocal is that your winter tire brand/model selection matters much more than the width—especially for the small difference I cited above.

YMMV

 

[PrudentOcean]

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