Not sure on tire pressure when going up in wheel size (17x7 to 18x8). I have been told that the tires need to be inflated to 38-40 lbs. and that these should run a little less than my stock 17's did at 33 lbs. 38-40 lbs. feels like I am riding on stones, but I don't want to go too low in tire pressure and take a risk of bending a rim, not to mention wanting to get the most mileage out of the tires.

What tire pressure do you run with 235/40-18?

Thanks!

36 psi in front
34 psi in back

Thanks! I will give it a try. I think I am at 36 all around right now.

does tire pressure matter with what rim size you are running. Like between a 18x7.5 inch rim compared to a 18x9? I have a set of 18x7.5 42 offset and getting 235/40/18 is the 36 front 34 back a good combination for that? Thanks

Are we talking cold psi or hot psi with those numbers?

I think we are talking cold. 35lbs front 33lbs. back seems to feel pretty good. That is the reading when tires are cold. I don't carry many people or weight in my car.