I changed my front sprocket today and I think I stripped the threads on the shaft that holds the sprocket, I was tightning the nut and it just kept turning. I didnt try to turn it the other way to get it off, I just left it on and put on the lock thingy that holds the nut. Anyone ever had this happen? What can I do now? Thanks guys!

 

Well, it sounds like it's stripped. Try takin it off, if it don't come off then you'll have to get a nut breaker to break the nut off the threaded portion. After that get a new nut (obviously) and find a tap and die set and use it to clean up the stripped threads. Your new nut should go on great after that, just don't tighten it as much as you would normally.