tyre pressure vs profile??

[moondog]

Hi, just a question about whether the optimal tyre pressure changes if you put lower profile tyres (on bigger rims) on your car. I've gone from 205/55 on 15" wheels to 235/45 on 17" wheels. I've seen a few previous discussions on another forum where some people maintain you should have a lower tyre pressure on lower profile tyres, but it was never explained or justified, and I can't see why, since it's pounds per square inch.

Thanks for any advice.

[Luke@tirerack]

you should always stay with what the auto manufacturer recommends for air pressure because no matter what size tire you have on a car the air inside that tire still has to support the same vehicle. If anything you coul;d use slightly more air pressure for added wheel protection

[moondog]

cool - thank you. I didn't think it ought to change, but was just a mite confused by what I'd seen a couple other people say.

cheers,

Raf