I'm pretty sure that you guys have already talked abou this for years, but I need somehelp with figuring out what the number/date markings mean on my 1970s Campy NR and SR crank arms. Here is what I have. I have 5 sets of Cmapy NR cranks and the numbers I have on the arms are circled numbers 1, 2, 3, and 4, and I also have number 3 and 4 inside of a diamond on the inside of the crank arms. I thought that they referred to the date, but I wasn't exactly sure what the circle and diamond mean -- maybe the decade?
Best,
-Dave Gordon
Los Angeles