Hello everybody!
Could you tell me please, what pressure should be in 98 Camaro Convertible with 245/18R/40 sizes?
Thank you!

 

whats it say on the tire for max pressure? i run my 245/45/17s at 38, if memory serves max is 50.

 

Look on your door jamb. Remember, if you inflate higher than recommended, you will experience a firmer ride and more NVH...

 

You forgot better gas mileage too, due to higher inflated tires having less rolling resistance. Find a happy balance between what the door sticker said and the max pressure of the tire. Car manufacturers may not want to prescribe higher tire pressures because tender bottomed owners would complain about a harsher ride.

 

Well my Camaro SS says 30 psi on the door jamb, the Owners Manual says run at 38 psi or max on the sidewall, whichever is less if you will be running at high speeds - so that's what I ran at Road America which easily gets upto 130 mph...

When you have more aftermarket suspension changes (lowering springs, SFCs, firm configured Koni SAs, etc.), having a more door jamb psi may help with ride quality for a DD. I tend to stay around 32 psi in general.