Many of the cast aluminum wheels use an alloy that is pretty much in line with a 6061 type composition (reasonably corrosion resistant) and for those in a -T6 type condition, I would expect the effects to be minimal. If we look at the strength at temperature and at the residual strength loss tables following exposure in the MIL-HDBK-5/MMPDS for 6061-T6 following exposure at 400° F for , there is a knockdown in ultimate tensile strength (Ftu) of about 4% and pretty much no knock down in tensile yield strength (Fty). Flipping over a couple of pages to the effect on percent elongation, again pretty much no impact which would tie in with the information regarding Fty.

Even if we bump the exposure up to ten hours at 400° F, the residual strength knock downs are still in single digits for that material. I realize that we are talking wrought product vs cast product and there are some behavior differences but in general, they follow the same trends. I know that there are some wheels out there made from casting alloys that instead of being solution heat treated and aged (the -T6 above for example) are solution heat treated and overaged as part of the production process (generally done to increase corrosion resistance but at the expense of strength) and I would expect to see more problems with those if run through an additional heat cycle.