Originally Posted by
Danielle
With the park tool chain checker, do you replace at .75 or 1. When does the wear start damaging cogs?
At .75, you should be changing the chain soon. "Recommended"
At 1, you should change the chain, period. "Highly Recommended"
The chain will start damaging cogs around .7, actually. If you're at 1, take a look at the cogs + chainrings. You may need to change those very soon as well.