How long is a piece of string? How much water is there in the ocean? Did the chicken or the egg come first and how long does a road bike chain last?
Well you should be because the answer to this question lies in a number of variable factors which we will come to in a minute. Rather importantly though, if your chain is excessively worn it can lead to a number of potential problems.
Worn bike chain problems
The chain is obviously one of the most important components in your drive train and it’s also the one that comes under the most stress and strain. It’s not a particularly glamorous component but it’s condition will have a big impact on the overall performance of your bike.
A dirty or worn chain won’t run as smoothly, easily or quietly as a clean, well lubricated new one and the difference between the two, in terms of the effort required to transfer the power from the pedals to the road is really noticeable! If you’ve ever ridden a bike with a rusty, dirty chain you’ll know what I mean!
Other symptoms of a worn bike chain include the chain slipping or jumping over the cogs in the cassette under load, gears not engaging smoothly and the teeth of cassettes and chainwheels being broken and worn.
How long will a bike chain last?
When a bike chain is said to be “worn” it basically means that it has stretched due to the constant load it’s put under. This stretching makes it increasingly difficult for the chain to remain firmly engaged on the cogs and it starts to slip and behave erratically. The amount that the chain stretches over time will depend on a number of factors for example the quality of the chain and the materials it is made from and the type of cycling use it gets.
If you are a relatively low power cyclist then the chain will obviously last longer than if you are constantly powering up hills or pushing really hard at a low cadence. It always amazes me that something as tough as a bike drive train will basically stretch and wear under such circumstances whilst our bodies will adapt and strengthen! Our joints repair and maintain themselves constantly to deliver the millions of movements they are asked to do over our lives whilst the best mechanical components we can produce just wear out and fail! Awesome!
It also depends on how well maintained the chain and drivetrain is. If the chain is constantly dirty the grit particles will slowly wear away at the chain joints and it will wear more quickly. A clean and well lubricated chain will obviously last much longer. This can also be effected by the overall riding conditions as a chain that’s used in dry conditions will by default probably last longer than one that’s been ridden in the dirt and the wet all the time.
So in terms of time, it’s difficult to say how long a chain will last. In terms of mileage cyclists tend to report chains lasting anywhere between 3000 and 10000 miles. Do people really keep an accurate ongoing record of their mileage? Well obviously some do and if you are a long time user of Strava you will be able to see your long term mileage easily.
How to check for a worn bike chain
Having said that a worn chain is a chain that’s been stretched you might think that it’s quite easy to spot but we are talking about only a fraction of an inch in wear which can make all the difference. If you think about the number of links on a bike chain and imagine a tiny amount of stretch in each one though you will realise that, multiplied by the total number of links on the whole chain this can soon add up.
There are a number of strange ways that apparently allow you to see if the chain is worn that include lifting the chain and seeing how many teeth you can see on the chainwheel but the easiest and most accurate way is to buy a chain wear indicator tool. This is a relatively cheap, easy and accurate way to see if the chain has stretched.
Basically you lay the tool on top of the chain and see if it will lay flat or not. there is then a very simple indicator that tells you if the chain needs replacing or if it’s OK to continue using it for a bit longer.
Replacing a bike chain
Luckily, replacing the bike chain is a relatively easy and inexpensive job. You can do it yourself but you will need a link breaking tool to take the chain off and to possibly make the new one the correct length. Some people also say that you should replace the cassette when you replace the chain and this really depends on the amount of wear on the cassette teeth. If the chain has been worn for a while the cassette teeth are likely to have rounded off a little and it is false economy to replace the chain and not the cassette.
However, if the chain hasn’t worn excessively then, in theory at least, the cassette should be fine. It’s often worth replacing the chain regularly and not letting it get near to the end of it’s life to protect the cogs on the other parts of the drive train. Chains are relatively inexpensive and the hassle and increased expense of replacing a cassette or chain wheel makes this a good policy!
So, the takeaway point is to keep a close eye on your chain for wear. Using a chain wear indicator tool is quick and inexpensive and will allow you to get the chain changed before it causes any wear to the other parts of the drive train – it’s really false economy not to do this!
You can make the whole chain and drive train last longer and run more smoothly by keeping it clean and well lubricated as well as perfectly adjusted. In fact this cleaning and lubing really is part of the pleasure of cycling as a smooth, silent well lubed bike is an absolute joy to ride. Whatever you do just don’t allow your chain to get dirty and rusty!