so i have 225 40 18" tires..... the max psi is 50 but i put 40 is that good??? since on the stock's were 32 in the front and 29 in the back?? should i have 40 psi all around? or more or less in the back?

 

30-34 psi is good enough.

 

so should i keep them as stock then? 32 in the front ? and lets say 30 in the back?

 

i have mine 32 front & 30 rear.

 

32 all the way around.

 

and it doesnt matter if its an 18" rim then?

 

^^^Doesn't matter.

 

I looked at my girlfriends tC with the optional 18" wheels. The door jam recommends 32front/29rear. Same as stock 17".

 

You should be 2 pounds higher than stock for every plus size. If you run 18's add 2psi over stock....run 19's add 4 psi over stock and so on. Yes it does matter.

You can also find this info on discount tires website.

 

34 Front....30 in Rear!

 

THat sticker is not based on the optional 18's. That sticker is standard on all the tc's assuming al have the 17's. Since Wheels are added later down thre ine the sticker stays the same on all models.

 

shouldn't matter as much... stock psi of 32/29 is fine for all wheels on the car.

 

On the sticker it even says 18". I'll take a picture on Monday, that's when I'll see her again.

 

Bump with picture. This might be helpful for anyone else curious as to what the recommended pressure for 225/40-18 tires are.

 

^^^Always good to show proof!

 

INtersting info. I still wouldn't suggest 29 on a 40 series tire though. I run around 2-4 plus over stock.

 

I use to run 34 psi in front and 31 psi in the rear and I wore my tires out unevenly. I switched back to 32 in the front and 29 in the rear and my tires wear out evenly. I have 18's so I would stick to the sticker specs.

 

good info. will run this setup when i get my wheels in.

 

PWND!

 

x2!