JDohn2001

I just got new 17"x11" ZR1 wheels and 315/35-ZR17 BF Goodrich T/A KD tires for the rear of my car. What should my tire pressure be for normal driving. Right now I have them at 35psi.

Jason

JDohn2001

Anybody?

Xride

should say right on the side wall, but i think 32-35 psi is about average for a tire.

Injuneer

You can't go by what is marked on the tire sidewall.... that's the pressure required to achieve the marked load rating, at max rated speed. On a 4th Gen, the 315/35-17 isn't loaded anywhere near max rating (1,874#), and the center of the tread would bulge considerably at the 44psi that is (probably) marked on the sidewall... I know that's what's on my 275/40-17 KDW's and also on my 315/35-17 Drag Radials.

I run 30-32psi in the DR's with not problems..... good traction, reasonable ride. The KD's would probably be happier at 32psi. Give it a try, paying particular attention to the tread wear. A tread depth gauge is an excellent investment when running wide, expensive tires.

Skyrider

I also have Nitto P315/35/ZR17 on 10.5" rims on the rear and P245/40/ZR17 on 9.5" rims on the front of a 2002 Z28. I have been looking for guidance on tire pressure that would give even wear. This is a weekend street driven car so I am not looking for race performance. I have seen pressures quoted that range from 22 to 35 psi. Any guidance from the forum would be appreciated.

Injuneer

As noted above, I found 30 - 32psi to be the best for street use. The only reason you might go below that would be track use.

The 245/40-17 is a bit tricky to predict. That's a 24.7" diameter tire and 1" smaller than it should be. The rears tires are correct at 25.7". The SS and WS6 coupes for example, came with 275/40-17 (25.7") tires. Are you sure you don't have 245/45-17 (25.7")? In any case, I'd say 32-34psi would probably be best.

As noted above, get a tread depth gauge, and monitor the tread wear for evenness.