The only downside I've had with the vortex is when they do go they start snapping teeth quickly. When my first one started snapping off teeth I ordered a new one, by the time it got here (had to mail order) I had 8 teeth left on a 45 tooth sprocket. It was nearly 20k miles when it happened though. People seem to swear by the new super sprockets or something like that. I think Ricksta has one on his R1