Originally Posted by
jgwilliams
I have a chain gauge. I've actually not had it that long so was a bit surprised on testing some of my old bikes that there was no measurable wear on some very high mileage chains. I was equally surprised on testing the PC 1110 chain to find it was well stretched. It's a simple two-sided gauge with .75 and 1.0 (mm I presume) markings. I would change a chain once it got over the .75 marking.
The only other bike which goes through chains that fast is my Brompton which got ridden in all the worst conditions and was thoroughly neglected. That's gone through 2 chains in 5,000 miles.
Nope, not millimeters. It’s % elongation. For the Park CC-3.2 chain checker, Park says
...indicate when a chain reaches .5% and .75% "stretch," the points at which most chain manufacturers suggest replacement. For 9 and 10-speed chains, replace chain just as the gauge fits the 0.75% side fits flat into the chain. For 11 and 12-speed chain, replace as the 0.5% side fits.