Joined: Jul 2015
Posts: 7,344
Likes: 3,206
From: NW Oregon
Bikes: 1982 Trek 930R Custom, '91 Diamondback Ascent w/ XT, XTR updates, Fuji Team Pro CF road flyer, Specialized Sirrus Gravel Convert, '09 Comencal Meta 5.5 XC, '02 Marin MBX500, '84 Gitane Criterium bike
they even vary between brands of chains or gears, within the respective "gear counts".. I recall measuring a selection of KMC, SRAM, and Shimano 6-7-8 sp.chains once....they were all a tiny bit different, even between two different models of KMCs of that group... i went with the shimano to reduce occasional noise from an annoying cassette...
and then, there's Campagnolo.. they exist in a world of their own, but are still fairly similar.