How dangerous is it to have a back sproket that makes a bit of noise when you back the bike up? I have been told by a friend that rides that my back sproket has little tiny grooves on it and thats why it makes a clicking noise when I back the bike up? My chain is in really good shape so would you normally change the chain with both sprokets. Also my bike is quite heavy around 425 I think. Would uping the teeth on the back help lift the front tire off the ground? I know uping the teeth will give the bike more bottom end and less top, should it also help lift that front tire up?