[mman1506]

We sometimes used them on our practice bot because they were cheaper and didn't wear as fast as our blue nitrile wheels. The tread is quite hard but the grip is fair (it's a lot like the old grey tread sky way wheels). After a while they would wear and leave the tread with a powdery feeling which reduced their traction significantly. I probably would not use them in competition unless you couldn't afford anything else. Vex's new hex Colson are a better option