Mustang wheels- does size change matter?
 

ive got a 6 cylinder with stock 16'' rims but i wanna get 18's. Do i have to get the gauges recalibrated to the new rims?

No you simply run a smaller sidewall tire. As the rim gets larger you just use a smaller sidewall to keep the overall height of the tire the same. Thats what matters not rim size.

OH and this belongs in tire tech, moving...