Vernier caliper for chain wear measurements

Discuss light weight issues concerning road bikes & parts.
DaveS
Posts: 2803
Joined: Fri Mar 24, 2006 1:26 pm

by DaveS

If you have chains off the bike and want to measure the true change in pitch, make your own full length gage. With most chains being the 52.5 53.5 or 54.5inches long without the quick link, 0.5% wear is an increase in length of about 1/4 inch or 6-7mm. I found a common framing nail that fits well, through the pin holes in the chain. I drilled a shallow hole in my work bench and inserted a shortened nail into the tight fitting hole. Carefully measure 52.75, 53.75 or 54.75 inches or the metric equivalent from the center of the nail and mark those lengths. Place one end of the chain over the pin and pull it tight to check the length. If the center of the pin hole at the opposite goes past your mark, you have exceeded .5% elongation. Since the total length that is being measured is so long, it's much easier to see how much longer the chain has become. Another option is to mount a precision ruler at the end where the elongation is to be measured.

I had some old 11 speed chains that were partially used, from last year, before I switched to 12 speed. The two Campy chains showed no significant elongation over their entire length, but the cheap KMC X11.93 chain, with about the same mileage, was well on it's way to .5% elongation. That's the same type of result I got 10 years ago with 10 speed chains. Cheap chains often elongate quickly and Campy chains will most likely never reach .5% elongation before other parts of the chain are shot.

I tried Campy's suggested method of measuring between the rollers with calipers and found the KMC chain at the 132.6mm limit while the Campy chains were both still under 132mm.
Last edited by DaveS on Sun Feb 16, 2020 9:27 pm, edited 1 time in total.

by Weenie


DaveS
Posts: 2803
Joined: Fri Mar 24, 2006 1:26 pm

by DaveS

I finally got around to measuring a new Campy chain. It measured 131.6mm. The recommended 132.6mm worn out length represents a increase of 0.76%, but the majority of the increase will be from the holes in the rollers, not an increase in the chain pitch. If a full length pitch measurement was made, it would be a small fraction of that percentage. Whenever I get a chain with 132.6mm between the rollers, I'll check the percentage increase in overall length to compare.

ghostinthemachine
Posts: 56
Joined: Thu May 07, 2015 9:18 pm

by ghostinthemachine

DaveS wrote:
Thu Feb 13, 2020 5:17 pm
Another option is to mount a precision ruler at the end where there the elongation is to be measured.
Seen this done in a team van on the end of a tool chest. Pin at the top. Rule rivetted to the bottom in the correct location with a sticker with nominal and max lengths of the however many lengths of chains they had (TT bikes, Road bikes, Cobble bikes, tall riders bikes, climbing bikes blah blah blah.) Over length, it went in a bin, under length it went in a box for reuse.

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