When To Replace a Bike Chain? – The Ultimate Guide

Close up view of a worn bicycle chain

The chain is a wearing part of your bike, it is important to know how to change it at the right time.

On average, manufacturers recommend a replacement every  2000 miles (3000 km) for road bikes and 1000 miles (1500 km) for mountain bikes.

When I perform the diagnostic of a bike that comes into the shop, this is the only step for which I use a tool. This makes the information 100% reliable. It is also possible to check the wear of the chain manually, but it is less accurate.

The chain is the element of the bike that is subject to the most stress, whether it be friction, tension, or weather-related. The common consequence of this will be the stretching of its links.

It is therefore interesting to understand how to increase the life of its chain and the consequences of its excessive wear.

How to know if a bicycle chain needs to be changed?

With or without a tool, there are 2 methods to determine when to change the chain on your bike. The method with a tool is always more reliable, that’s what I would recommend to you.

Check the wear of your chain with a tool

You can measure the stretch of your chain with a chain wear indicator. This tool measures the distance between a given number of links. Depending on the tool model, fixed or variable data, place it anywhere on the chain.

Close up view of a man's hand holding a bike chain wear indicator

In the case of the fixed, if it is fully inserted for data :

  • 0.75 – the chain is to be changed.
  • 1.0 – the string and the cassette are to be changed.

In the case of the variable, insert it and read the displayed data. Same rules as above.

The pitch (the gap) between 2 links must be half an inch or 12.7mm or could be that due to wear the pitch has increased by 0.75mm or 1.0mm.

Checking the wear of your chain without tools

Although less precise, it is possible to get an idea of the wear of your chain without tools. When buying a used bike for example.

To do this, place the chain on the large chainring and pull on the middle link of the chainring. When pulling, if the chain shows more than half of the tooth then the chain should be changed.

Understanding the principle of stretching a bicycle chain

To understand the stretching principle of a bicycle chain, we need to look at its constitution.

The latter is composed entirely of metal elements with a limited lifespan:

  • Pin
  • Roller
  • Internal plate
  • External plate

The assembly of these elements constitutes chain links:

  • Male link = 2 internal plates + 2 rollers
  • Female link = 2 external plates + 2 pins

The whole of the links connected between them created the chain.

The friction and tension applied to all of these elements cause “normal” chain wear if it is well maintained.

Tips for making bike chains last longer

The most significant factor in chain and drivetrain wear, in general, is external stress. Dirt and water can significantly shorten the life of a chain if it is not properly cleaned and lubricated.

Although there are protective coatings such as anti-rust, nickel, or titanium nitride, your transmission maintenance is essential.

It has been shown in the laboratory (under optimal conditions) that a good quality chain can offer efficiencies of approximately 98.6%, which is huge for a wearing part. It should also be noted that a dry chain could lose up to 30% of its efficiency.

Note that the wrong adjustment of its transmission will have an impact on its wear.

To ensure the “normal” life of your bicycle chain, it is undoubtedly through its maintenance.

Here are some tips:

  • In dry weather, wipe down your chain and lubricate it every 2-3 rides.
  • In wet weather, dry and lubricate your chain every ride.

In both cases, remove your bike chain regularly (every 10 rides) to clean it with soap and water. The more regularly you wash your chain, the easier it is to do and the longer the life of your chain will be.

  • Always lubricate after washing.
Man changing a bike chain with a chain breaker

What happens if we don’t change the chain on our bike?

The use of a bicycle chain will wear out the entire transmission. So the next time you change the chain, the cassette and chainrings will surely have to be changed. It is generally said that every two chain changes the cassette is changed. A too-pronounced wear will have a direct impact on the efficiency, the friction will be too important, the tension too light and the gears less precise.

Finally, breakage occurs more frequently with poorly maintained equipment.


You can now know when to change your bike chain with or without tools, with more or less precision.

Keep in mind that the maintenance of your equipment is the key to extending its life but also to your comfort of use and your safety.

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