Knowing when to replace motorcycle chain and sprocket is crucial to prevent unexpected failures that can lead to damage. While it’s rare for chains to fail, improper maintenance and lack of care can cause them to wear out faster than expected. In my experience, it’s all about regularly assessing the condition of both the chain and sprockets, watching for signs of wear. The key factors to consider include how much wear has occurred and the amount of slack in the chain. Using this guide, you can look for signs that suggest it’s time to replace the parts before they fail and cause further damage.
Related: How to Restore an Old Motorcycle
How to check for chain and sprocket wear
For the most accurate results, it is best to use a center stand or paddock stand during this process.
1) Pulled out!
Inspect the swingarm adjusters. If you have reached their adjustment limit (meaning the wheel is pushed back as far as it can go), it is time to replace both the chain and sprockets.
2) Stretched out
If your chain has become stretched out, you may notice a gap between the sprocket teeth and the chain links, especially when pulling on the chain at the rear. This clear gap indicates that the chain is no longer fitting snugly around the sprocket, which can affect performance and safety. To fix this, you can check the tension using a tool like the Chain Monkey and adjust the tension accordingly. Keep an eye on these indicators, as maintaining proper tension will help prevent further wear on both the chain and sprocket.
3) Tight spots
If you notice tight spots when checking the chain tension, it’s a sign that something’s wrong. To check, rotate the wheel and look at several spots along the length of the chain for areas that feel tight. If the tension differs significantly from the rest of the chain, you’re likely dealing with stiff links. In my experience, a thorough clean and re-lubrication can often help, but if the issue persists, it may be time to consider a replacement. Always check these spots regularly as part of your routine maintenance, and refer to our best practice guide for cleaning a motorcycle chain properly.
4) Sharp teeth
When inspecting your sprocket, make sure to examine the teeth all the way around. If you notice any damaged or broken teeth, it’s a clear sign that it’s time to replace the sprocket. This is especially true if the teeth have become sharp or worn down. Remember, alloy sprockets tend to wear out faster than steel ones, so pay extra attention to them. A sprocket with sharp or worn teeth can significantly affect the performance of your chain and bike.
5) The good book
Always consult your motorcycle’s manual to check when the chain and sprockets need to be replaced. Every rider has different riding habits, so while the manual provides essential information, take it with a pinch of salt. You also need to consider other factors like how many track days you’ve done or how many miles you’ve put on the bike. If you’re not a smooth-riding commuter, you’ll likely need to replace your parts much sooner than someone who rides more casually.
What should I replace?
As experts in chain care, we highly advise replacing both the chain and sprockets at the same time to ensure optimum performance and peace of mind. While it’s not always necessary to replace them together, from our experience, it’s best to keep things simple and consistent. Replacing them together ensures better performance and prevents future problems, so don’t wait too long to replace both parts.
Replacing your motorcycle's chain and sprockets
When it comes to replacing your motorcycle’s chain and sprockets, it’s a job most riders can tackle at home if they have the proper tools. To start, you’ll need to securely lift the rear of the motorcycle in order to remove the rear axle and wheel. If you don’t have the equipment for this, consider taking it to a local shop. A helpful tip: if your rear tire is also due for replacement, have the shop replace the chain and sprockets at the same time to save on labor costs.
Before getting started, make sure you have all the correct parts ready to go. While it’s always a good idea to replace the chain and both sprockets as a set, you might not need to replace everything if you’ve been staying on top of chain maintenance. For instance, my 2018 KTM 250 XC-W chain was nearing the end of its life. The rollers were loose on the rivets, and I could pull the chain slightly away from the rear sprocket. Since I caught it early, I only needed to replace the front sprocket and chain. The rear sprocket was still in good shape, with no visible wear.
An opposite example would be when Editor Lance replaced the chain and rear sprocket on one of his bikes but kept the same hardened steel front sprocket. Unfortunately, the new chain meshed poorly with the worn sprocket, making a terrible noise. He quickly replaced the front sprocket, and the noise disappeared. This shows that even if the sprocket looks okay, it’s important to check for things like teeth that are sharp, hooked, or have flat areas. If you notice these signs, your sprocket might be toast.
Related: How to Remove Rust from Bike Chain
Cost
The cost of replacing your sprockets and chain varies depending on the type of motorcycle and parts you choose. For a small, lightweight motorcycle, a plain chain may cost as little as $20, while a high-quality O-ring chain for a bigger, more powerful bike can run over $200. O-ring chains have built-in lubrication within the links, held in by rubber O-rings between the side plates, which allows them to last longer and perform better.
For the sprockets, the front and rear can cost anywhere from $50 to over $250 for a set, depending on the size, materials, and expected lifespan. If you’re tackling the job at home, you’ll also need a chain tool to break the old chain and rivet the new one. These tools typically cost between $40 and $90, but they’re a one-time investment that can last for years.
Additional chain drive information
When you check your manual, it will provide important details about the size and length of the chain you need to buy. Common sizes like 520, 525, and 530 refer to the pitch, or the distance between rivets in eighths of an inch. For example, the “5” means five eighths of an inch, and the “20” refers to the width of the roller or the distance between the inner plates, also in eighths of an inch. It’s crucial that the chain width matches the sprocket width.
One of the great advantages of chain drive in motorcycles is that chains and sprockets allow for easy changes to your overall gearing. To lower engine speed below a specific speed, you can, for instance, make the front sprocket one tooth larger or decrease the size of the rear sprocket if your motorcycle feels like it is “revving too much” at highway speeds. On the flip side, decreasing the sprocket size will increase acceleration. If you choose to fit a larger sprocket, just make sure there’s enough clearance. Otherwise, you can always go with stock sizes when buying new sprockets.
Other parts to consider replacing
When working on your motorcycle, don’t forget to check other important components. Chain sliders are often overlooked because they’re usually black and covered in grime, but these rubbery pieces keep the chain from dragging or sawing through the swingarm. On off-road bikes with a lot of suspension travel, you may find additional parts like upper and lower sliders, rollers, and possibly a lower chain guide to help maintain proper chain tension. Make sure to inspect these parts for wear when you check your chain and sprockets.
If your bike is old or has high mileage, it’s also a good idea to inspect the cush drive rubber dampers in the rear hub while the wheel is off. These rubber pieces help to reduce abrupt driveline forces and can wear out over time. Checking and replacing these parts can prevent unnecessary wear and ensure smoother riding.
Related: How to Tighten a Bike Chain
