Just installed the Sprocket Specialists 14-tooth countershaft drive sprocket from Baja Designs ($17) on my Chopper. Let me tell you, what a difference this makes in the low-end performance! No more lugging from first to second. The gearing is so much tighter all the way around! I can't believe I waited this long to install it (had it for about three weeks now and was waiting for the new 130/90-18 rear, but couldn't take it anymore). Perfect fit, no problems & an easy swap. Can't wait to hit the dirt now! If you can live with losing about 3-5 mph from your current top end cruising speed, I highly recommend changing out the jumbo-sized 15-tooth stock dog. You won't regret it.