Shimano Chains

You need a Shimano chain that matches your number of rear speeds: 6, 7 and 8-speed bikes share one chain width, while 9, 10, 11 and 12-speed bikes each need their own narrower chain. Linkglide drivetrains need a Linkglide chain, and 12-speed Hyperglide+ systems need a 12-speed Shimano chain for smooth, reliable shifting under load.

Shimano designs its quick links for single use and recommends a new one each time the chain is joined, because a link that has been opened can loosen. Use a quick link matched to your chain's speed, close it under pedalling tension, and check that both pins are fully seated in their slots before riding.

Measure your chain with a chain checker and replace a road chain at 0.5 percent elongation or a mountain bike chain at about 0.75 percent. Skipping under load, slow shifting and visible side play are other signs. Checking every few hundred kilometres lets you replace the chain before it wears out the cassette and chainrings.

Most Shimano chains come with 116 or 126 links and are shortened to fit your bike. The usual method is to wrap the chain around the largest chainring and the largest rear cog, bypassing the derailleur, and add two links. Full suspension bikes also need a check at full compression before the chain is cut.

Many modern Shimano chains are directional, with the stamped logo or markings facing outward away from the bike, because the inner and outer plates are shaped differently to help shifting. A chain fitted backwards still runs but shifts less smoothly. Check the instructions that come with the chain, since older 6 to 8-speed Shimano chains are not directional.