Originally Posted by
NoWhammies
I've been using a chain checker tool (similar to the one in the image below) to determine when I need to change my chain. Right now my tool is telling me the chain is at 50% life/wear.
Yet when I do a search online re: when to replace a change, I'm getting mileage/distance recommendations. Frequently in the 2,000 to 3,000mi range (
https://www.bicycling.com/repair/a20...ur-bike-chain/). This seems kind of young/early to me.
I replace my Campagnolo (C8, C9, and now C10) chains after 4000-4500 miles when shifts onto my big ring get sluggish due to increased flexibility from excessive side plate wear although they've only elongated 1/32", and expect to replace my cassette with the next one now that it has 25,000 miles on it. Probably not coincidentally, when I've checked using my dial calipers this was just a little more or a little less than the distance between rollers Campagnolo recommends as the wear limit.
I ran one off brand chain in the Pacific Northwest that was approaching 1/8" after 2000 miles. Your mileage may vary.
So I'm torn. What's best practices? Replace the chain by distance or when the chain checker tool says the chain is at 75% life?
Use a $1 ruler or $30 Shimano TL-CN42 because every chain checker that measures between rollers is inaccurate.
Put tension on the chain, measure between the same point on pins which should be 11" apart, and replace at 11 1/16" (1/2%).
That will omit roller wear which doesn't increase pitch and therefore impact cog life.
Usually people use 12", although 11" means you'll have fractional marks to line up with the end on a standard ruler.
Replacing at 0.56% elongation instead of 0.52% is a 0.0048 inch difference that's too small to matter.