Ok, let me explain…. I am not disputing that a chain tool measures chain stretch as a percentage of overall chain length, and I am not disputing that it is 0,25%, 0.5%, and 0,75%. Some context…. A while back I was going through GX Eagle chains very quickly, and some people on the hub were making big claims about the life span of XX1 chains. I decided to try that, and for curiosity’s sake I wanted to measure how the chain was stretching accurately. So here is what I did, which should explain my initial post a bit better. I replace my chains at 0.75% - that is my “allowable” amount of stretch. To measure I take a vernier calliper, and measure the length from the inside of a roller to the inside of another roller with 10 links in between. For the sake of my explanation let’s say that measurement is 100mm on a new and unused chain. I then took a chain at 0,75% wear and took the same measurement, let’s say for this explanation that this measurement was 110mm, thus giving me an allowable stretch of 10mm. So, if the measurement reads 102,5mm that means I am at 25% of allowable stretch. When it gets to 110mm I am at 100% of allowable stretch, and it is time to replace. Again, I am just using these numbers to explain the concept. As I used my new XX1 chain I take this measurement often, after a considerable amount of km, I am not even at 25% of allowable stretch. Hopefully that clears it up? On the stretch/wear thing. Chains can wear (degradation of the material) and stretch. Bicycle chains generally speaking stretch before the material degrades, and that’s why we measure stretch. Okes really need to relax, this isn’t a foreign policy or religious rights debate. We’re talking about chains.
