PVC slicks, the Nylon hubs capture the slicks from both sides for a quick changeover. Wear is part of the whole experience and what makes it work. We tried different plastics, Nylon, ABS, Delrin and PVC. All have their own slip feeling. PVC is the homegrown standard.
Just found this on gizmodo:
Manufactured by Razor — they of roller blade-wheeled scooter fame — the little Crazy Cart ($350) found fame after its inventor, Ali Kermani, filmed this pint-sized tribute to Ken Block’s Gymkhana films, called “Ken Box.” That’s Ali driving and doing battle with the gorilla.
$800 and the Crazy Cart XL is yours Lew. 