Matching a Shimano chain to your bike
Shimano's chain codes look cryptic but they resolve to one thing: the number of sprockets on your cassette.
- CN-HG40 — 6, 7 and 8-speed
- CN-HG53 — 9-speed
- CN-HG54 and CN-4601 — 10-speed
- CN-HG601 — 11-speed
- CN-M7100 and CN-M8100 — 12-speed
Chains get narrower as the speed count goes up, because the sprockets sit closer together. That is the whole reason they are not interchangeable. Fitting an 8-speed chain to an 11-speed cassette does not work, and forcing it damages both.
Quick link or pin
Some of these ship with a joining pin, others with a quick link. A quick link is easier to fit and lets you take the chain off for cleaning without a tool. If the box says W/QL you have one; W/PIN means you are joining it with a pin and a chain tool.
Replace it before it takes the cassette with it
A chain stretches as its pins and rollers wear. Past roughly 0.75% elongation it stops matching the tooth spacing of the sprockets and starts grinding them into its own worn shape.
Change the chain at that point and everything else survives. Ride it to 1% and beyond and the cassette is usually finished too — a much more expensive conversation. A chain checker costs very little and pays for itself the first time it is right.
Common questions
How often is that, in kilometres?
There is no honest fixed number. It depends on the surface, the weather, how you ride and how well the chain is looked after. A well-lubed road chain lasts a great deal longer than a mountain bike chain ridden through winter Tokai. Measure it rather than guessing — or come past the shop and we will measure it for you.
Does the lube really matter?
More than the chain does. A clean, correctly lubricated chain lasts far longer than an expensive one run dry. See chain lube.
