Signs of a worn chain and sprockets

Chain and sprockets wear together, and running a tired set costs more than replacing it on time. November is a good moment to check: the bike sits more often, so you have an hour to do it without rushing.

• Put the bike on a stand so the rear wheel spins freely, and turn it while inspecting the whole chain.
• Look for stiff or binding links: the chain should flex evenly, without jerks or crunching.
• Pull the chain away from the rear sprocket at the bottom. If it lifts so far that you see almost half a tooth, the chain is stretched.
• Inspect the sprocket teeth: hooked, shark-fin shapes or one-sided wear mean replacement.
• Check for rust on rollers and side plates and for missing seal rings. Adjusting the slack won't fix these.
• If the chain has stretched, replace the set: chain and both sprockets together.