Hey all - out on a ride today and towards the end of the day started to notice an odd problem with my GPX. The problem occurs (or is noticeable) at low speed, usually when accelerating from a stop. I get the feeling of a crunching/clicking feeling from the rear wheel as it accelerates (kinda feels like it's got a huge stone stuck in it, as it clicks faster as I increase speed). I don't think it's audible, but it is a very distinctive feeling. At first I thought the sprocket may be damaged, or their might be a dodgy link in the chain. Couldn't spot anything when I got home, tho, so unless it's a problem on the front sprocket, I'm not sure what it is. Any ideas? Oh, not sure if it's related, but if I crack the throttle open full, there is an odd vibration in the bike, that seems to happen at any speed/revs (more noticeable doing say, 70km/h in 5th). Related issue?