I am having problems discerning the correct length of a cup/cone spindle I am trying to replace. I have measured this spindle with two different instruments; one shows it to be a 124mm spindle, while the other shows it to be a 122mm spindle. The spindle is stamped 3S, and by Sheldon Browns website this spindle should be a 121.5mm. I would trust this number except the A and C lengths differ from that which Mr Browns website indicates this spindle to be. I need this number to achieve a good chainline for a fixed gear bicycle I am building for my wife.
Am I making this too difficult and should I just take the spindle specs per Mr. Brown as gospel?
Thanks everyone in advance.