i was wondering why noone posted then i looked at the post and nothing was there, dont know what happened to it. my question is on my tire it says "50 psi max pressure" but half way around the tire it says "never exceep 40 psi to seat beads" so what should the psi be? i have 225/40-18 toyo proxes Fz4

 

When you have the tire on the rim but bead not seated, you pump it up until the bead "pops" on..lower profile tires ( I can say from experience that your size is exceptionally difficult to seat) are stubborn and don't always like to seat easily. So your standing there over an unseated tire on the rim clamp pumping air into it. If it hasn't seated by the time the press gauge on the machine reaches 40psi, stop, let the air out, lube the bead and try again. And I think the 50psi is at operating temp. the pressure will rise about 1 psi for eveery 10 degrees of temp rise. So always chech tire pressure at operating temp..or is it the other way around? Someone help me out here.

 

just remember that those numbers are for maximum tire pressure. As in never exceed. Normally you wouldn't (and shouldn't) put that much pressure into your tire. Except for some special circumstances like you're autocrossing and want to prevent tires from rolling to its sidewall (not likely anyway with such low profile tire). Remember, as you drive, tires heat up and the air inside expands, increasing pressure. Plus too much pressure causes tires to bulge slightly and cause the center of the tire to wear out sooner than the rest.