Just passing on some info here that i acquired from speaking with tire manufactures.
I have been asking this question for a few months now as i was planning to upgrade my tires and wheels if necessary.
After explaining that i'm willing to spend the money to upgrade my wheels as well , it was explained to me by 2 major tire distributors so far, that i could safely upgrade my ST c rated 50# tire to an ST D rated tire at 65# and still use the OEM 50# wheel. Both said to " not spend the money to buy new wheels for a "c" to "D" tire upgrade" and that's a 15# difference in the wheel. There is a built in margin of safety into the wheels PSI rating. Sometimes when we inflate our tires to max, the centers wear. That was the case with mine. It was recommended to me to under inflate by 5 lbs to get them to wear evenly. That's what i did and all has been fine for 5000 mi so far.
They never run hot, i check the temps with a digital gauge. :R I know..i know...i treat them like children. My DW is trying to get me some therapy.