Q: How can I tell if my cassette is worn? My local shop says it needs to be replaced, but it’s not that old.
A: Don’t forget that chain and cassette wear is something that needs to be monitored simultaneously. Most people will wear specific gears more than others, but the combination of a worn chain and new cassette will lead to expedited wear. This will lead to inconsistent shifting. Most of the time it is the worn gears that actually shift better, and the less used gears are rough because they are not meshed with the worn chain. If you are changing a cassette, then it would be wise to replace the chain, too. The exception is if the cassette is fairly new and you are just changing ratios. On the flip side, a cassette can go through about three chains as long as the chains are changed before they wear too much. Get a quality chain checker, and every few weeks check it while you lube your chain, that way it becomes a habit.