Yoshi
02-10-2006, 06:47 PM
How much do you hardcore weekend racer guys know about tire contact patches and sidewall effects on cornering?
Sooner than expected, my other pair of rims arrived today. Finally i have a matching set! yay! So now I'm running 17x9 in the rear with 215/40... it occurred to me that I have several half used up 215/40 pairs sitting in my garage... so on they went to the new rims (front) 17x8. Here's the question:
If I have a 17x8 w/215/40 and it's a slight stretch, and 17x9 w/215/40 which is a pretty big stretch. Normal logic would suggest that even tho the rims are "staggered" there should be an extremely minimal effect on handling differences between running the same size rims all around... but the tires are not solid rubber, but filled with air, and will contort... so where does that leave the affect on cornering?
This is beyond my basic knowledge of physics :)
I'm assuming that the rather aggressive stretch on the 215s on a 9" rim would yield a slightly larger contact patch, and depending on tire pressure, could equivocate more or less traction vs. the 8" wide 215. THUS if the front tires have more give due to sidewall flex vs. the 9" 215, which is practically incapable of flexing due to the stretch; then oversteer (vs. say 17x8 215 all around) would be maintained correct? Am I making any sense? That was a lot of babble :)
This obviously isn't taking account other suspension goodies, just tire tech alone in a speculative enviornment.
Cliff Notes:
same size tires on different width rims. The stretch will minimize the expected affect of understeer inherent in a staggered wheel width setup, as long as the wider/stretched tires remain in the rear.
True or False?
Sooner than expected, my other pair of rims arrived today. Finally i have a matching set! yay! So now I'm running 17x9 in the rear with 215/40... it occurred to me that I have several half used up 215/40 pairs sitting in my garage... so on they went to the new rims (front) 17x8. Here's the question:
If I have a 17x8 w/215/40 and it's a slight stretch, and 17x9 w/215/40 which is a pretty big stretch. Normal logic would suggest that even tho the rims are "staggered" there should be an extremely minimal effect on handling differences between running the same size rims all around... but the tires are not solid rubber, but filled with air, and will contort... so where does that leave the affect on cornering?
This is beyond my basic knowledge of physics :)
I'm assuming that the rather aggressive stretch on the 215s on a 9" rim would yield a slightly larger contact patch, and depending on tire pressure, could equivocate more or less traction vs. the 8" wide 215. THUS if the front tires have more give due to sidewall flex vs. the 9" 215, which is practically incapable of flexing due to the stretch; then oversteer (vs. say 17x8 215 all around) would be maintained correct? Am I making any sense? That was a lot of babble :)
This obviously isn't taking account other suspension goodies, just tire tech alone in a speculative enviornment.
Cliff Notes:
same size tires on different width rims. The stretch will minimize the expected affect of understeer inherent in a staggered wheel width setup, as long as the wider/stretched tires remain in the rear.
True or False?