We could safely say the chain is your bike’s beating heart. Keep it in a healthy state, and your ride will be smooth. Dirt, grime, or a stretched chain will make your ride miserable. Today’s lesson is knowing when to replace the chain. The chain consists of multiple links holding rollers (bushings) and pins together. The rollers can wear down or get pushed back into the links (i.e., stretched).
To measure your chain’s health, Park Tools (or any bike mechanic) has a chain checker gadget that will give you a pretty good measure of the chain’s wear. This tool sells for $12-15. I use Park Tool CC3.
The Chain Checker has two numbers — mine shows .75 and 1.0.
Think of these numbers as the percentage of the chain that has stretched. The .75 means 75% of the chain has stretched, which means replace the chain as soon as possible. A 1.0 means 100% of the chain has stretched, which means replace the chain NOW!
To measure, start by placing the curved tip in the chain link.
If the .75 end rests on top of the link, your chain is healthy, and you are good to go.
If the .75 end slips down between the links, flip the tool to the 1.0 side.
Checking both numbers will help you gauge whether the chain has stretched 75% or 100%.
Park Tools also offers tools with .5 (50%) and 1.0. Personally, I don’t bother with 50% of wear since I know there is time, but I leave that choice to your discretion.
Assessing your chain’s condition a couple of times during the season may prevent you from having a rotten day on the bike.
For Club members: Lina carries this tool (and she knows how to use it!) so if you’re hanging out with her after a club ride, have her show you how to check your chain wear!