Vernier caliper for chain wear measurements
Moderator: robbosmans
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.
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.
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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.
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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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And now at last... To answer my own question. This is how it is done properly (machine transaltion of the guide, stolen from some russian cycling youtube blogger, I am sure he won't mind):
1. We need a caliper. Measure the chain clean (preferably).
2. Count 10 links. Any other quantity can be used (A)
3. Insert the (upper) caliper jaws between the rollers. Rice. 1.
4. Record the obtained distance (Y)
5. Measure the roller diameter (fig. 2) and write down (Z)
Formula.
C = (Y + Z-A * 12.7) /A*12.7
C - chain stretch in%
A = The number of links along which the measurement is carried out
Z - Roller diameter (outer)
Y - Distance obtained by measurement.
1. We need a caliper. Measure the chain clean (preferably).
2. Count 10 links. Any other quantity can be used (A)
3. Insert the (upper) caliper jaws between the rollers. Rice. 1.
4. Record the obtained distance (Y)
5. Measure the roller diameter (fig. 2) and write down (Z)
Formula.
C = (Y + Z-A * 12.7) /A*12.7
C - chain stretch in%
A = The number of links along which the measurement is carried out
Z - Roller diameter (outer)
Y - Distance obtained by measurement.
I have retired from this forum, not wasting any more time here.
What vernier calipers do you gentlemen have? I went off the deep end a bit regarding verniers, whenever I see them in thrift shops, second hand shops or flea markets I buy them. Such an elegant measuring tool. Actually found an Mitutoyo one in a flea market once, paid peanuts for it...
I have digital models from harbor freight. $10 when on sale. I've ground down the sides of the tips to get between the outer plates more easily, but I don't use them to measure chain elongation. Use a 12 inch rule or full length tape measure for that. I have a 60 inch length of a tape measure with a pin fixed to my work bench at one end. Place one end over the pin and measure the true elongation over the full length.
Calipers are good for measuring roller wear. Most of the wear will be on the holes in the rollers.
Calipers are good for measuring roller wear. Most of the wear will be on the holes in the rollers.
Check your measurement method, I see 132.1 on a C11 that has been ridden *once*. 131.6mm sounds like you are sampling between outer links and the caliper is resting on the ends of the inner links, not touching the rollers at all
Cheap one (from a supermarket where the local manager apparently has/had a bit of a habit of stocking disproportionate amounts of everything non-perishable the chain the store belongs to occasionally puts on offer, great place to browse cheap oddities)erolorhun wrote: ↑Sun Aug 22, 2021 4:49 pmWhat vernier calipers do you gentlemen have? I went off the deep end a bit regarding verniers, whenever I see them in thrift shops, second hand shops or flea markets I buy them. Such an elegant measuring tool. Actually found an Mitutoyo one in a flea market once, paid peanuts for it...
Feelers dremeled down to low profile for reliable rollers contact (see previous post, mod posted before)
I think it's a stupid way to measure wear, but the difference between new and shot must be greater than 0.5% since you're adding roller wear to true elongation. Even then most what you're measuring is wear on the rollers, not elongation, but that's how Campy chains to wear.
But the 132.6 measurement includes the wear between bolt and inner link plate eleven times while the wear between roller and inner plate flange is only included twice. I believe that people make far to much fuss about the rollers wear difference.
Side note: my mystery "near invincible" chain has finally breached 132.6 at 16500 (assuming that it's indeed the first chain I installed on the bike which I believe it is), the Pedro's "excludes rollers wear" gauge is still considering the chain almost new.
Side note: my mystery "near invincible" chain has finally breached 132.6 at 16500 (assuming that it's indeed the first chain I installed on the bike which I believe it is), the Pedro's "excludes rollers wear" gauge is still considering the chain almost new.
The wear on the hole in the roller can be 20-30 times greater than the pin and inner plate wear. I never take measurements between rollers unless that's what I want to know. Then I measure between rollers on adjacent outer plates. A new chain often measures around 1.200 inch.
As a long time campy chain user I can second the observations of daveS and others that campy chain elongation is minimal compared to binning at 132.6. What's nice to consider is that bushing wear is not as detrimental to cog life as pin to pin elongation which results from side plate wear around the pin plus pin wear. I typically resale my chains for a nice price at around 132.2nm which typically is about 1/32" in 1 foot (=1/8 inch for the full length. Distance ? About 3k miles using rock n roll gold each 125 miles.
One thing we should keep in mind when contemplating chain elongation is that wear is not linear: manufacture-time surface treatment is only good for so many nanometers of abrasion and larger gaps allow more contamination ingress. Mileage gain per additional tolerated elongation might be surprisingly low.
Speaking of gaps, has anyone run through the trigonometry of inner/pin gaps with regard to wear? There must be a certain amount of gap even when new, to allow cross-chaining, and I wonder how many percents that gap would grow for at certain amount of "exclude rollers" elongation. That factory new minimum amount of gap will also have to be bigger for wider chains (unless they are designed for narrower cassettes). I suspect that this is responsible for the majority of chain durability increases that have been observed between "one more cog" generations, and not just materials progress.
Speaking of gaps, has anyone run through the trigonometry of inner/pin gaps with regard to wear? There must be a certain amount of gap even when new, to allow cross-chaining, and I wonder how many percents that gap would grow for at certain amount of "exclude rollers" elongation. That factory new minimum amount of gap will also have to be bigger for wider chains (unless they are designed for narrower cassettes). I suspect that this is responsible for the majority of chain durability increases that have been observed between "one more cog" generations, and not just materials progress.
When I performed a wear test by deliberately using a Campy 10 chain for 6000 miles, it showed little elongation, but large amounts of wear on the holes in the roller and a large increase in the side clearance between inner and outer plates. I had a record 12-25 cassette in use and it ruined the two most used sprockets 19-21. I made a plug gage from a 6mm hex wrench, ground thin enough to slip between the rollers. If that plug gage went through, there was a lot of internal roller wear.
A new chain usually has about 0.1mm or .004 inch of side clearance. Twice that is very worn.
A new chain usually has about 0.1mm or .004 inch of side clearance. Twice that is very worn.
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