A worn chain isn’t the same as a dirty chain although this often comes together. The latter is easily managed with some MucOff Drivetrain cleaner and chain lubricant, but a worn chain can have bigger and more costly implications.


A worn chain may reduce shifting performance, power transfer and also wear your rear cassette and chainrings more quickly. With more expensive cassettes and chainrings, it is worth checking and changing the chain more frequently. At the time of writing, sourcing parts can often involve delays where you are left without a working bike.


However do note that a chain doesn’t stretch, it elongates. With use, the material is removed from the pins and bushings of each link, over 100+ links this cumulative degradation makes the chain longer. The precision of a drivetrain means that the links no longer match the sprockets or the chainring, and the longer chain then wears the other parts to match. No problem until you add a new chain that is shorter and then slips – then the cost goes up needing to replace the cassette and maybe chainrings too.


Monitoring chain wear and changing in time can:

  • Save money by prolonging the life of the cassette and chainrings.
  • Maintain the performance of the drivetrain – lost power and shifting precision with stretched chains and bigger gaps in cassette teeth.


You can easily check your chain yourself:

  • Chain measuring tool. Cheap, easy and effective. A simple guide that shows the wear and dictates when to change the chain.
  • Measure with a 12-inch ruler. Line up a rivet at zero, then count 24 rivets and your 24th rivet should be at the 12 inch mark. if the 24th rivet id more than 1/16th of an inch past the mark then your chain should be replaced.
  • Miles. Not so accurate but a simple method to just remember to change every 800 – 100 miles. This will vary depending on the use, the load, the conditions and the terrain – or just get a chain measure!


Bicycle chains come in many forms and you need the correct one. Single, 7,8,9,10,11, and 12 speed. SRAM and Shimano are usually compatible, Campagnolo uses its own design, and KMC offer chains that work across all drivetrains (although some would argue not as well as a genuine part). SRAM Eagle also requires its specific chain as the design is different from all of the above. And all manufacturers of course recommend using their own chains for optimum shifting.


Bike chains also come in different grades – budget to top end. The main differences are in the materials used, the weight and durability from these factors. Personally, I choose a mid-range chain and replace it more frequently, as a top-end KMC, Dura-Ace or Super Record chain will cost far more.


If your cassette has excessive wear this is sometimes visible as the teeth on some sprockets will become more pointed. If you put a new chain on this cassette the chain would slip. Often if a cassette is ‘part worn’ there is a mild slip on some sprockets, but after a few miles to bed the chain in, you can get another chain’s worth out of the cassette. This varies depending on wear, and sometimes it’s only a problem on one or two of the heavily used sprockets. It’s not perfect, but may prevent a cassette replacement if you can endure the bedding in!


The chainring is worn if the teeth start to look like shark fins. However, the good news is that chainrings tend to last longer than cassettes, and usually, you only need to replace the worn part. A worn cassette may not mean a new chainring is required as well. Chain slipping is the ultimate tell, however, it is worth looking for wear as this will mean inefficiency in the chains ability to deliver the power from the chainrings to the sprockets and rear wheel.


In summary, changing your bike chain regularly will help prolong the life of your cassettes and chainrings. A cassette will last several chains if changed in time, and will also keep your shifting and power delivery at its very best.


Any metal components taken off the bike should be recycled!


If in doubt, contact Revolution Cycle Sport in Billinghurst, a chain check is quick and free, a chain change and gear adjust is a quick job, you will save money in the long term and better still, your bike will run to its best.