Originally Posted by
Billy22Bob
1. I've always wondered if going wider adds friction...
My physics class would so NO...but I am all ears to those who know the
real world and what they know from experience (
as opposed to myth and folk law)....
As an engineer, I know that friction does not depend upon surface area. As a car nut, I know that wider tires have better traction. How do you explain this contradiction?
note: 255/40's is as wide as we can go on our SLK32's 17" rims, where as you SRT guys are pushing 285's on 19's...= much more contact area.
2. Another thought as well was a discussion around how much wider on a rim can you go..
My thoughts are - if your tire is much wider than your rim, the tire wall will bulge and not provide the cornering stability you may want from time to time. The SLK32 has 217mm rims (8.5") - so with 245/45/17 tires as spec you get [14mm overhang] on each side.
With my 255/40's I've increased that to 19mm and you can definitely tell (visually).
3. But....does this added bulge help you with hookup?
Much like the top fuelers - as you hook - you have some absorption in the tire wall which stores energy and helps you even out hookup. Is this a real consideration?
Low profile tires would obviously work in the opposite direction = harder to hook. Is this your experience?
Would I get better hookup if I went to a 16" rim with a 245/45? There are factory SLK32's that came out with such a tire configuration.
What type of engineer? If you go to TireRack there is a ton of info there. Under tire info for each brand is a min and max wheel width for each tire width. and the recommended width. You are correct in assuming that too wide a tire will result in some sidewall bead instability. It will also decrease your footprint unless it is run under inflated. I wouldn't do it despite what a lot of guys have said on this forum. Your biggest footprint will come from the largest tire you can fit both width and diameter. Smaller wheels with bigger ratio tires will have equal contact area as bigger wheel with lower ratio tires, width being equal but the softer sidewall of the smaller wheel higher ratio tire combo may help you hookup a bit better. But will not be as stable in high speed cornering.