“Chain skip” is one of the most common drivetrain problems riders experience. This is when your chain slips forward while pedaling under much pressure. There are a few things that cause this problem: stiff chainlink or worn freehub body. A worn out chain is a very common problem.
Overtime, a chain will “stretch” (But it’s not actually stretch. The pins that connects the links wear and turn into a letter D shape extending the pitch of the chain). Such chain “stretch” is actually the bushings and pins starting to wear which causes them to skip. When your chain wears, your chainrings and cassette also wear along with it. Replacing the chain before it starts to wear too badly will dramatically prolong the life of your drivetrain (cassette and chainrings). A $50 new chain every couple of months (or earlier if you regularly ride on rough conditions), could save you hundreds by preserving your drivetrain. So, it’s important that you know how to check chain wear and replace your chain before it could damage your drivetrain.
Check Chain Wear
If you do not have chain measurement tool, here is a much easier way to check chain wear.
1. Shift the gear so your chain is in the big ring and the smallest gear is on the cassette.
2. Pull the chain at the front of the chainring. You will know if your chain is beginning to wear if it starts to lift off the top and/or bottom of where it’s positioned on the chainring teeth. Such “lift” is because of the stretched chain which is no longer positioned on the teeth properly.
Consider internal gear hub bikes which need less maintenance and repair.
Measuring the Chain
Once you have found out that your chain is worn, check how badly damaged it is. If it is “lifting off” on your chainring, you have to replace it.
Here’s a more accurate way to measure chain wear:
With the chain still on your bicycle, get a 12-inch ruler and place the zero inch mark directly above the center of one of the chain pins. Count 12 complete links, wherein one complete link equals one outer and one inner. A rivet on a new chain must be line up to exactly 12 inches on the ruler.
If the rivet is less than 1/16″ past the mark, you don’t have to get a new chain. If it is between 1/16″ and 1/8″ past the mark, you need to replace your chain and keep your sprockets. If it is more than 1/8″ past the mark, you need to replace your chain as well as your cassette.
The front chainrings generally do not need to be replaced very often. They are very easy to spot when worn, as they start to look like shark teeth (see photo below). Know that if you keep on using an old chain, your drivetrain will also be damaged and you will be left with hundreds of bucks in repair costs. So, it is best to chain your chain at the point when it barely starts to “lift off” your chainrings.
Watch this video to learn more tips on how to check chain wear.