The Z06 wheels weighed 19.0 lbs on my bathroom scale that has .5 pound resolution. Depending on the scale, you could easily get a bit above or below 19 lbs. As a strong, cheap, and readily available factory wheel that closely meets the specifications, it seems likely that it was the wheel in mind when the current CMC rule was made. The fact that it is no longer cheap or all that available isn't really relevant. The rule wasn't created around the Enkei wheel as that wheel wasn't even legal until the rule was changed to allow including the spacer weight in the calculation.

I don't think changing the allowed wheel weight (up or down) is a good idea. Up will make some people's wheels illegal. Down will send a bunch of people scrambling to buy new wheels. Allowing wheel spacers to be included in the weight is the easiest/cheapest way to get everyone to an equal spot. There are a lot of cheap wheels available for the Mustang but they are usually in the 22 lb range. There are wheels that cost a bit more but they come in below weight. The Enkei wheel costs about the same as the going rate for the a good Z06 wheel. There is really nothing in the marketplace for the Mustang that hits the sweet spot like the Z06 wheel without including the spacer in the weight.

I do think not requiring the wheel spacer to be welded to the wheel is a good idea. Welding a billet spacer to a cast wheel of an unknown alloy isn't a good plan and could even be dangerous in some cases. I also don't get the point? A light weight wheel is only legal with a spacer and checking for a spacer at impound is trivial. It also takes wheels that would be AI legal/desirable and makes them CMC only so they are harder to sell.


Richard P.