I have a bell on every bike. I have a Knog on a roadbike- it sucks and is too weak to be heard half the time. Most have Spurcycle bells which are the best and loudest. One MTB has the Timber bell which is okay- mid level sound. I don't like the fact that I can't ring it when on smoother trails going uphill or flat since it needs a bit of rough terrain to ring. It is nice on the DH though. Overall, the Spurcycle is my favorite.