[Boxstard]

Originally Posted by DreamSign

Ok, let me throw another shrimp on the BarBi...

If I went with 205 45 17 instead of 205 40 17 the Overall diameter is + 3.7% from stock
If I went with 245 45 17 rear instead of 255 40 17 the Overall is + 2.5% over stock.

Given there would be a 1.2% mismatch in RPM per mile compared to the stock OAD, Would this cause a problem with the computer, or ABS?

For the 17" wheelset I want to swap onto the 5 speed car, The rears are currently new 255 40 17 Firestone Indy 500s I just bought on the drive down from Canada, and the front tires are older and need to be replaced anyways.

What if I kept the current (less than 1000 miles on them) 255 40 17 in the rear and added the .2" taller than stock 205 45 17 @ 24.3" OAD vs the 245 45 17 at 24.1" OAD?

Basically this way I'm adding +5 to the sidewall profile, while keeping about the same weight of the tires. This 'should' soften the ride over the bad roads a tiny bit, probably enough to move the needle a tiny bit?? What say you?

You are downsizing the wheels from 18” to 17”, right? Then you are essentially adding more sidewall even with the stock tire size. Matching front sizes would be 205/ 50 or 225/ 45 if you are to keep 255/ 40 rear.

45 or 50 is the aspect ratio, so the number alone does NOT determine how thick the sidewall is; it also depends on the tread width. For instance, 255/ 40 tire has 102mm sidewall while 225/ 45 has 101mm.

I just switched from Michelin AS3 to Pilot Sport 4S. Grip is phenomenal and way better as expected, but I’m surprised by forgiving ride quality.