99horsey

Assuming the contact patch area is an ellipse, the area is the product of the 2 radii and pi. Assuming the radius across the width increases but the radius across the circumference does not, the area of the contact patch increases by the same ratio as the increase in width. So an 8.5% increase in width equals an 8.5% in contact patch area.

Based also on your point that the tread pattern of two of the same tires in different widths will not be exactly the same as far as tread blocks to grooves, there are really too many variables to look at. And even if someone had a tire in a 235 width and installed that exact same tire in 255 width, their observations would be based more on old 235 tires vs. new 255 tires. In short, I asked a completely unanswerable question!

Thanks for the help. I think I'll go for the wider tires for the better dry traction and hope that wet traction is at least as good.

hootie_john

Funny that this came up now. I have the factory 18" Bullit and was thinking about going to a bit wider tire (still have the factory KSW 235/50 on them) when time to get new tires comes around. My car is my DD, so wet traction is important for me as well.

99horsey

Well, I went ahead and set up an appointment to get the 255s installed Friday and it's supposed to rain Saturday. I'd say I'll provide feedback but I guarantee I will be impressed with the new tires compared to the current since they are shot and were never that good in the wet. I think (and hope) everybody who said a small width change means nothing compared to a good wet tread pattern is right.

S stang

I have that size on my 06 gt drive all the time on them,even autox them in the rain one time,when I did not want to use my race tires,like them .live in central ill.