5 Key Bike Parts and How to Tell When to Replace Them

Marc Lindsay
by Marc Lindsay
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5 Key Bike Parts and How to Tell When to Replace Them

Your drivetrain — the parts that make your bicycle move forward — all wear at different rates. The hard part is knowing when they need to be replaced because doing so at the right time can save you money and boost the overall performance of your bike. Otherwise, those worn-out parts can wear out other parts and cause a much bigger problem.

To make sure this doesn’t happen, here’s a list of five common bike parts and how you can tell when they need to be replaced so you can ride faster, be safer and save a little cash in the process.

The Chain

Your bike chain is the one part that probably needs to be changed most often. It’s also the part that can cause the most problems for your other parts like your chainrings, cassette and derailleurs when it wears down, while making your shifting unpredictable. In general, most chains last about 2,000–3,000 miles. This number varies depending on how clean you keep your drivetrain, the weather conditions you ride in and your power output.

How to determine if it needs to be replaced: A chain checker is a fairly inexpensive tool that can determine the wear of your chain. Simply insert the tool in between the links. If it reaches 0.5%, your chain still has life left. If it reaches 0.75%, it’s time to replace it.


If you change your chain regularly, then your chainrings should last a really long time. However, whenever you change your chain, it’s also a good idea to check your chainrings to make sure they’re in good condition. Along with normal wear and tear, the teeth of your chainrings can also become damaged from poor shifting technique, crashes or from being banged around during storage and transportation. When the teeth are damaged, the chain may slip off the chainring when riding or shifting or catch as you try to pedal.

How to determine if it needs to be replaced: Inspect the teeth. If they become hooked like shark’s teeth or feature a noticeable ramp in profile compared to the more gradual rise of a new chainring, they need to be replaced.


Just like your chainrings, if you change your chain when you’re supposed to and keep your drivetrain clean, your cassette will last longer than your chain. One common sign your cassette needs to be replaced is if you experience skipping after purchasing a new chain. Visual wear may be harder to notice because of the number of cogs, and because wear may only happen on the one or two cogs you use most often.

How to determine if it needs to be replaced: Grab the rear brake lever to hold your wheel tight. Push down on one of your pedals with the brake applied and watch for upward movement of the chain on your cassette. If it does move as you press the pedal, your cassette probably needs to be replaced.

Housing and Cables

Your housing and cables directly affect how smooth your shifting and braking is. This causes issues with performance and safety that can easily be corrected by replacing these parts before it begins to affect other parts of your drivetrain.

How to determine if it needs to be replaced: Cracks, breaks or broken pieces of your housing are signs the housing needs to be replaced. Damaged housing places more stress on your cables, which can cause it to break during a ride. Frayed cable ends and rust are other signs the cable has weakened and needs to be replaced. On average, your cables and housing should be replaced every year if you ride three days per week or more.


While not technically part of the drivetrain, your tires are an important piece of equipment that needs to be replaced frequently. Lightweight racing tires can last 1,000 miles or less, while heavyweight commuter tires may last as long as 5,000 miles. But no matter what type of tire you use, there are a few easy ways to tell when your tires have had enough. If your tires are the same size, you can rotate the front and back tires to increase their longevity since the rear carries more weight than the front.

How to determine if it needs to be replaced: Nicks, cuts and wear are all common. However, if you can see threads or the tire belt, your tire is too worn to be safe. Likewise, any cut or gash that exposes the inner tube is not safe to continue using. Some tires may also have wear indicators that help to let you know your tire is worn before a gash or tear happens. Bald spots on tires with tread signal that your tires need replacing.

About the Author

Marc Lindsay
Marc Lindsay

Marc is a freelance writer based in Scottsdale, Arizona. He holds a master’s degree in writing from Portland State University and is a certified physical therapy assistant. An avid cyclist and runner of over 20 years, Marc contributes to LAVA, Competitor and Phoenix Outdoor magazines. He is the former cycling editor for Active.com.


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