One idea that I had been kicking around for a neighborhood basher (and I am NOT suggesting this as a viable option for this class) is to use the HPI F1 car's front and rear axles on a car as they both have TC-sized hexes. I have an F10 and haven't put TC/USGT/VTA tires on it to see how wide it would be. On the VF1 thread, we'd kicked the ball around on how to have scale treaded tires for those bodies. Using FGX or F10 hexes was the only viable idea I'd had. With the 1s spec, I still wish that we could use rubber tires, not foam. It would remove much of the minimum diameter issue. Unfortunately, we never came up with a good way to convert pan car hubs to 12mm hexes without the expense of a machine shop.