Last week I was searching through my American Express online statements and my Gmail trying to figure out when I bought my Wippermann Connex 10S0 chain. The reason is that I thought it should be showing wear by now, and I was starting to worry about it.
I worry about all sorts of strange chain-related thins. Is my measuring technique wrong? Is the chain damaging my drivetrain? Am I at risk for another catastrophic failure of the chain during the ride? I needed to answer these questions for my own obsessive-compulsive reasons, and if I could determine when I bought it, I could estimate mileage, which I could then use as another data point in my chain wear assessment.
Unfortunately, American Express doesn't provide easy access to statements that far back, so I have to rely on measuring the chain wear. I religiously maintain my drivetrain, measuring chain "stretch" with a go - no go gauge (shown in the below photo). I bought the gauge last December, and I know I had my current chain before that. I bought my Garmin Edge 305 in October 2008, and I had the chain before then too. Since October, I've ridden over 1500 miles. So, the chain has at least 1500 miles on it, and probably more like 2000-2500 miles. I measure it every time I clean the drivetrain, and have not seen any wear...until last Friday.
On Friday night, while cleaning my bike and drivetrain in preparation for Saturday's ride, I measured the chain stretch. Surprisingly, the 0.75% side DID engage in several places, but the 1.00% side did not. The chain is finally showing some wear! It felt a little odd, but I was actually happy that the chain was showing measurable wear. Otherwise, I would continue to question whether the Spin Doctor gauge was made to specification and was actually measuring correctly.
As I mentioned, I probably have over 2000 miles on the chain. Based on a little internet research, this seems fairly typical. The chain doesn't absolutely need to be replaced at 0.75% stretch, but it does absolutely need to be replaced at 1.00% stretch. Since I want to keep turning smoothly, and I have a spare chain on the shelf, I'll install it next time I clean the drivetrain.
I guess I'll have to find another source of worry. Unseen cracks in my carbon frame are near the top of the list!