The first round were junk. I'm not sure if it's the same people manufacturing them this time or not. The issue is you cannot gear a single speed application for enough take off to have any speed, or enough top end to have any take off. They did not hold up well to slippage/abuse. TAV's have come a long way and are hard to beat in my opinion. For all out drag racing a centrifugal clutch still seems to be the winner on a mini...