few questions about Subaru traction in snow, the other day here in NEPA we had a snowstorm, roads were bad. well in the meantime my son went in a ditch during this time, so i get in my wife's 16 Forster and off to get my son, the forster was great in the snow with new tires , so this brings me to the next question, my son wants to get a new Subaru Forster, but he wants to get the Sport model which has 18" tires, i am thinking that the sport model with these larger tires and might even be wider. may not be the best choice for winter conditions. would the Premium model with 17' tires be better.

 

chet

Edited November 17, 20187 yr by chetc
mispell

I'm no expert but my thought would be that larger, wider tires would have more rubber in contact with the ground which should provide more grip. Now, how much difference would there be between those two? I don't know, probably not a ton.

I'm interested if I'm correct or not.

My opinion wider tires are not better, they trap the snow under them and not let the tire get down to something more solid. That said, the difference you are talking about will not matter, I have had this issue on pickup trucks with wide tires on them, they suck in the snow.

Wider tires to a point have less traction in snow because there's less weight per square inch on the tire. 

 

But just because the rim diameter is bigger doesn't mean the width is. My 18' Limited Crosstrek has 18" rims and the width is nearly exactly the same as the 17"

 

Edited November 17, 20187 yr by golucky66

talk to any competent tire shop and they will tell you that you want narrower for snow.

 

'16 has 225 60 17 IIRC. The 18" might be a 235 wide, but I don't remember. 225 vs 235mm section width is less than 1/2" or basically no difference

Yea, winter traction is all about PSI between the tire and the ground. Reducing the tire's width, reduces the square inches of the contact patch, therefore increasing the PSI.

You also want the tires to flex, so the more sidewall the better.

The exact opposite of summer traction.

 

If you were to spec a winter tire/wheel set (through Tire Rack or similar), they would recommend the smallest wheel that will fit over the brakes. So if you get enough snow to justify a winter setup, that's something to consider.

Your kid just put a car into a ditch and so you buy them a NEW Forester?  I'd start with something you won't miss if it gets wrecked...