Checking chain stretch

Why: Knowing when to replace the chain means you will avoid having to walk home after a chain breaks from lack of maintenance

From the manufacturer’s website for my tool: A worn chain shifts poorly and wears sprockets at an accelerated rate. The CC-3 is a “go, no go” gauge designed to accurately indicate when a chain reaches .75% and 1% wear, the points at which most chain manufacturers suggest replacement. Made from precision, laser cut steel.

How:
Luckily, it’s quite easy. I use a chain stretch tool. They cost around $7, and are almost brainless to use.

There’s two sides, marked .75% and 1.0% – the amount of stretch in the chain. Placing one hook into the chain and letting the other side slot in between two links will let you know how much stretch there is. The flat side of the tool will rest on top of the chain when the chain stretch is less than 0.75%.

In this case, the chain has stretched 0.75%.

0.75% is the “preventative maintenance replace” mark. 1.0% is the “need to replace” mark. As such, this chain should be replaced to avoid excess wear on the rear sprockets.

Inspection interval:
Well, depends on the amount of riding. Probably once every 200 mi should be enough, which is about once every 2 weeks for me. Personally though – it takes 5s to put the tool in and check it’s ok.