There’s nothing more annoying than a clicky, jumping bike chain.
With bikes, it’s all about the drivetrain. Or maybe I should say drive-chain.
The chain is the primary power transmitter between your legs and the wheels, and without it you’re essentially helpless.
No wonder, then, that so many bicycle maintenance issues come down to chain integrity.
A remarkable number of cycling issues can be traced back to chain health, and it’s usually because people don’t bother to replace them, ever.
There are many reasons why your chain might be making noise, jumping around, or causing excessive vibration.
Here are four common causes.
1) Your bike chain is really freaking old
Yeah, this is probably the reason. People don’t replace their bike chain nearly as often as they should.
Chains stretch over time, which causes them to move around more, both horizontally and laterally.
When the links fit snugly to the sprocket, you won’t feel or hear a thing. When they’re worn out and stretched, that widened gap means they clatter around as you pedal.
That’s bad news. An old, loose chain will wear out your sprockets and chainrings.
In the shop, we use something called a chain wear tool to check for this; it measures the gap between your links. This chain wear tool by Park Tools is good and inexpensive.
It’s definitely worth attending to a worn out chain, especially if you’re restoring an old bike.
Note: a squeaky, clicking chain can also be caused by not regularly oiling your chain. So oil your chain!
2) Your chain is misaligned
A misaligned chain is another common woe. It happens easily: your spacers might be poorly placed, you might have the wrong sized wheels, sprockets or chainrings. Or (this is common) your rear wheel might not be centered.
Ideally, your chain should have a nice, straight path from rear sprocket to chainring. There’s some grace since chains have a bit of flex, but if it goes too far your components will wear down and your chain will start to click and jump.
Note: on a fixed gear bike you need a really taut, straight chain line, since there’s no derailleur to tighten the slack.
3) Your derailleurs need adjustment
On geared bikes, derailleurs push and pull the chain into gear. A poorly adjusted derailleur is an incredibly common reason for chain clicking and jumping.
Most shifters and derailleurs use a cable to adjust the gears. However, if that cable is too tight or too loose, the chain will want to jump out of gear.
That might indicate a worn out shifter cable, but it’s likely you just need a tune-up. Shifter-derailleur balance is a fine art, so I recommend bringing it to your local bike shop for adjustment.
4) You components are damaged or worn out
Components like sprockets and chain rings do wear out. This is the least common issue, so only address it if you’re certain (because it’s expensive.)
Often, a chainring will receive wear to the point that it can’t grip the chain fully anymore. Unfortunately, replacement is your only real option here.
Other bits and pieces that can wear out are: sprockets, derailleurs, shifters and cranksets. Once broken or worn down, no amount of adjustment will fix the problem.
Those are the four most common reasons your bicycle chain will make clicking noises and jump.
Other causes do exist, but start with this list and see where you end up. Thanks for reading!