3. SHIFTING CHAINS AND CABLES
Shifters are similar to brake levers; grease the moving spots, and typically you’re set. Shifter cables also fray and wear, and may need to be replaced.
These parts actually move the chain up and down the gears. They can be finicky and tend to be easily damaged, especially the rear derailleur. Clean these components once a month, and review this guide by Bicycling if you’re derailleur seems to be poorly adjusted.
BIKE CHAIN AND CASSETTES
We’ve already covered cleaning and lubing the chain, but make sure to check for wear and stretch when you clean. You can buy a chain stretch tool to measure, or simply go to the bike shop whenever it feels sloppy and ask them to check. If your chain is stretched or worn, you’ll need to replace it and the rear cassette, which wears with the chain.
Cassettes will show visible wear when they need to be replaced–think shark teeth instead of clean, unified sprocket edges. They’ll also shift poorly. If you need a new cassette, make sure you buy a compatible chain at the same time.
4. BIKE WHEELS AND TIRES
Your mountain bike wheels should freely spin around the hub without rubbing, touching, or hitting anything else. If the wheels don’t spin true, in a proper circle, they’ll need to be serviced. Problems include spokes, broken or loose, worn-out hubs, and possibly even damage to the rim.
Truing mountain bike wheels is not a basic maintenance task: Make sure you go to a professional if you don’t know what you’re doing. If you have a cracked rim, it’s unlikely that the wheel can be saved; better to buy a new one.
Tires are easy: Simply look for smoothed worn patches, cuts, tears, or other damage. If a tire is damaged, buy a new one right away. A worn tire will affect braking and steering, and a damaged one will likely cause a flat. It’s a good idea to buy an extra set of tires and keep them somewhere clean and dry.