Tuesday Tip: Determining Chain Wear

A couple weeks ago we were at a national-caliber amateur race, waiting for the next in a seemingly endless list of qualifiers to go off, when we spied something in the grass on the side of the track. Now there’s always a variety of goodies to be found on your average track. whether it’s goggles, stray plastic, ends of clutch and brake levers, and of course, plenty of tear-offs. But the shiny coiled specimen that attracted our attention was one very tired-looking chain that had obviously gone well past its intended lifespan before giving up the ghost.

Just for giggles, we picked it up by the ends, and laid it out sideways, to see exactly how worn it was. New chains will make a decent arc…something like a smiley face. This one had aspirations of making it into a full circle. The side plates were also worn from their customary hourglass shape into something more akin to a lumberyard—straight lines everywhere.

To give us a better idea of how to check for where so that you can determine when your chain should be replaced, we checked with Farrah Bauer from RK and Excel’s Marketing & Advertising Manager for some tips. When quizzed on the right way to measure wear, she told us, ” The most exact way to check for chain wear is to multiply the number of chain links by the pitch (.625 for 520, .5 for 420/428) to determine the length of the chain in inches. Then multiply that by .03. This gives you the maximum amount of “stretch allowed before a chain should be replaced. For example, 120 links x .625 = 75… times .03 = 2.25. Then add 75 to 2.25. The grand total is 77.25. So if your 120-link chain exceeds this length, it’s time to replace the chain.”

If counting links and doing the math isn’t your cup of tea, you can always go the low-tech route. Farrah must have seen our eyes glaze over during the previous math examples, so she told us, “In the real world, there are a variety of easier ways to determine when to change your chain and sprockets — when the sprocket teeth are obviously hooked, when you can pull the chain off the back of the rear sprocket 1/4, or when you have tight and loose spots. None of them are exact but they are all an indication that the time has come.”

She also mentioned, “To get the maximum wearlife out of you chain, you should always change your sprockets whenever you change the chain.”

Keeping an eye on the wear, combined with regular lubing, and cleaning, should go a long way to help prevent your chain from becoming a trackside souvenir.