Ok here's my story! Went out and purchased a new 51 tooth sprocket for my bike. Figured out the stock chain was too short so then I ventured out and bought a new o-ring chain. I installed the sprocket (Sunstar Aluminum), put the chain on and cut it to length. I set the chain to the spec tightness and tightened everything up. I spun the rear wheel with my hand and noticed that it was "dragging" somehow. Well I chocked it up to the chain being new and "stiff". I then compressed the brake piston on the rear brake and it spun more freely. Then I began to wonder. I double checked the alignment of the tire. It was good according to the marks, but I have heard they can be off. I rode at Muenster yesterday and noticed with throttle closed the bike would slow down faster than normal. Also the bikes rear brake would lock up with the slightest pedal movement. So now to my questions. First of all the bike is really new with no damage to the rear wheel, brake caliper, or swingarm. Rear wheel bearings are in good shape. What is a sure fire way to align the rear wheel in the swing arm? Is the rear disc so fragile (side load) that I could of bent it changing the sprocket? Is an O-ring chain really that stiff? I'm a pretty mechanically inclined person (aircraft mechanic) and have looked at everything visually. I guess I need to pull everything off and start with just the wheel and no brake. Then add brake with no chain. Maybe chain with no brake and try to isolate the problem. Also check disk run-out. Are these expensive? I need all input and method for wheel alignment, moral support, etc....