Question on newly bought 275/40/17 tires

IIRC, isn't the recommended tire pressure stamped on the tire itself? Might want to take a look at 'em (btw - are they drag radials?)

My stock 275/40/17s are ford recommended 32psi, but yesterday i stuffed 35psi in them. dont ask why, i just did.

Tire PSI

The main purpose of tire inflation is to hold some load. The tire stamping will you give the max load for it's stated inflation to carry that load which is always way more than the axle rating (GVAW). Therefore, since most passenger car axle ratings are much less than what the tire inflation and that respective load need to carry the PSI is reduced but enough to make sure it can meet the gross axle rating.

In the case of the larger 275 tires it just means that 32 psi can carry a little more load than the 245's. By the way the 245/45R17 's at 32 psi can carry 1390 lbs.for each tire or 2780 lbs for an axle.

After that some better handling might be better with higher psi but anything in the 32 to 35 psi range will be great for basic wear, handling, traction etc.