The slot car industry cratered so fast in '66-'67, there were a lot left over, and the stock circulates online.

Thingy cars didn't use them, and the hardbody RTRs were pretty much obsolete, usually didn't live long enough to wear out a set.

They were sold primarily by sizes, so they sorta hover around the scale sizes - Monogram had a competitive line the were alsoo quite good and they inclued them in their curbside kits sold to try to salvage some of their slot car investment.

The other opportunity - USCP, the Ukraine based 3D company sells this wheel and tire set for the current Revell E-Type (and, presumably, other Jags.) Perhaps the tires might be available separately?