If the wheels are wider than the tread, there's a bit more stretch in the sidewall... which stiffens them. At least that's the theory, and there are racers who use that to get more performance out of the same tire.
Jaguar, for the XFR-S (the "S" signifying that this is the "Sporting" R-model...
), widened the wheels about an inch without changing the tire model used, as part of the handling upgrade package.
I guess you can figure out if it's that or the rubbing that's causing the extra heat by pumping the tires right up and observing the extra heat goes away.