I am running 245/40/18 Front and 275/40/18 Rear.. what is the recommended pressure on these? Is it still 35 psi all around?

 

obviuosly you are talking aftermarket which i think really depends on the brand of tire. call the place that installed for you.

chances are though they wont know crap either and will tell you to just stay around stock. I went from the 17's to 19's wider all the way around and also was going through some alignement checks at the same time. after the algnment and the aftermarket falkens, i thought the car handled like crap, real soft.

then a guy at the alignment shop asked about the tire pressure and i said i was running stock numbers 35psi cold. he said that was probably it, too little air in much more rubber. so i went to 40 psi cold and noticed immediate difference, much more responsive. then i tried up to 45 cold and that was nice off the bat but after the tire heated up it got too bouncy. so back to 40 psi and thats what i am running.

moral of the story, you are better off just trial and error'ing it. all you need to do is check your tire manufacturer's cold psi limit, mine is 51, but i wont go near there. good luck.

 

I'm running pirelli pzero nero m+s.. the rears are much wider tires.. well, I'm getting an alignment this weekend so I'll see what they tell me