Originally Posted by
John_E
Have you tried to measure the chain checker itself with your caliper?
I hadn't, but just did. My caliper reads 5.02545" on a Shimano chain checker, i.e. a little longer than .05% elongation. Now, my understanding is that the checker's end should "fall' between rollers -- not being pressured, which I assume adds a tiny bit of length to the measurement. Bottom line, the checker seems accurate, if a little bit forgiving.
[Edit] actually, not sure at all. I've assumed that I could take the "outside" measurement, without any supporting evidence. Positioning the caliper correctly is difficult/impossible because part of the checker pushes rollers -- so the measurement will depend on how hard you push.