How to choose the right chain

Keeping your bike chain clean and well lubricated will maximise its life, but even the best cared for chain will slowly wear and stretch with use, and the performance of your drivetrain will gradually deteriorate. Shifting gear might not be as smooth as it once was, the chain could 'skip' as you pedal, or it might even snap, which could be dangerous.

A worn chain can also result in faster-than-normal wear to the sprockets and chainrings, so not changing it in time can end up being costly. For all these reasons, it's a good idea to check your chain regularly with something like a B'Twin Chain Wear Indicator. It takes seconds to find out whether it's time for a new chain.

If your chain does need replacing, here's how to choose the right one.

Replacing like with like

Bike chains might all look fairly similar but they come in various widths to suit different drivetrains. The number of sprockets on your cassette (the cluster at the centre of the rear wheel) is the important factor here. An 11-speed chain is narrower than a 9-speed chain, for example. If you own a BMX, it requires a different chain again. It's not complicated, you just replace like with like – 11-speed with 11-speed, 9-speed with 9-speed, and so on.

If your bike has a Shimano Tiagra 10-speed groupset a straight replacement would be a Shimano Tiagra 10-speed chain, but you could go and buy a new Shimano Deore HG54 10-speed chain and that would work too. 

You don't even have to stick with Shimano, though. You could go for a slightly lighter KMC X10-EL chain instead, or save some money by choosing a B'Twin 10-speed chain. There will usually be something on the packaging or in the marketing material that says: "compatible with Shimano and SRAM 10-speed groupsets", or something similar.

Fitting a new chain

Many chains are directional – they're designed to fit a certain way around. A Shimano CN-HG601 11-speed chain should have the branding facing outwards, for example, so always check the instructions before fitting.

You'll almost certainly need to shorten your new chain before installation by driving out one of the pins. Just count the number of links on your old chain and make the new one match, or you can also lay the new one out next to the old one – because chains stretch as they wear the old one may be two to three millimetres longer. Shortening the chain requires a special tool, like the B'Twin 500 Bike Chain Tool.

These days most chains are joined by a quick link that comes as part of the package. A quick link replaces one outer chain link and can be fitted without tools. Spare quick links are available separately. Like chains, they come in different widths – they’re marked 10-speed, 11-speed, and so on – so make sure you get the right one. 

Some quick links are hard to remove, so a B'Twin Quick-Release Bike Chain Tool could come in handy. Most quick links are one-time use only and should not be re-installed.

Looking after your chain

You need to keep your bike chain clean to maintain its performance and reduce wear. B’Twin Eco-Friendly Chain Cleaner and Degreaser and Bike Cleaning Brushes will get rid of the grime. 

Alternatively, try the B’Twin Bike Chain Cleaner. Used with a degreaser, this little device locks in place around your chain and contains rotating brushes that scrub the dirt away.

Rinse and dry your chain, then apply some lube – such as B’Twin Bike Chain Oil Lubricant – and you’re good to go. 

Drive belts

Some bikes (including several B'Twin Tilt folding bikes in the past) are specially designed to use a toothed drive belt instead of a chain to transfer power from the pedals to the rear wheel. 

Belts can't rust, don't need to be lubed, and usually last longer than chains. They're very low maintenance. 

However, the belt will need replacing if it gets damaged or the performance starts to deteriorate. Make sure you select a new belt with the same number of teeth as the old one. We offer a drive belt with 111 teeth and another with 112 teeth.

You’ll need to remove the rear wheel from your bike in order to replace the drive belt, but everything can be done with everyday tools.