How to check Sram AXS flat top chain wear?

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Alexbn921
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by Alexbn921

Topic says it all. I have an AXS force drive train and wanted to measure chain wear, but there are no tools available and when I laid it out with on a ruler, the spacing is smaller than 1” per link.
Over the entire length of the chain it’s about 1/32 of an inch short. I would expect it to be long with the 2200 miles I’ve traveled.


by Weenie


TobinHatesYou
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by TobinHatesYou

Alexbn921 wrote:
Fri Feb 21, 2020 10:17 pm
Topic says it all. I have an AXS force drive train and wanted to measure chain wear, but there are no tools available and when I laid it out with on a ruler, the spacing is smaller than 1” per link.
Over the entire length of the chain it’s about 1/32 of an inch short. I would expect it to be long with the 2200 miles I’ve traveled.

Pin pitch hasn't changed with SRAM 12spd road. It is still 1/2" between pins. And yes, the tool linked above works with any 1/2" pitch chain.

dannywin42
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by dannywin42

I heard on a podcast that the pin diameter is slightly larger than other 11sp and 12sp chains so normal chain checkers wont work, they will read low wear

Sent from my SM-G975F using Tapatalk


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Alexbn921
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by Alexbn921

TobinHatesYou wrote:
Sat Feb 22, 2020 12:04 am

Pin pitch hasn't changed with SRAM 12spd road. It is still 1/2" between pins. And yes, the tool linked above works with any 1/2" pitch chain.
My Park CC-3.2 dosn't work so I was going old school, but found the chain was short instead of long. Used 2 diffrent rulers too. Measuring the entire chain came up short as well.

TobinHatesYou
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by TobinHatesYou

dannywin42 wrote:
Sat Feb 22, 2020 12:20 am
I heard on a podcast that the pin diameter is slightly larger than other 11sp and 12sp chains so normal chain checkers wont work, they will read low wear

The rollers increased in diameter, but the newer chain checker prongs abut themselves against rollers on the "same side" instead of inside-inside. In reality, older chain checkers were never that accurate because you don't want to take into account exterior roller wear, just internal wear between the roller and pin.

DaveS
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by DaveS

A used chain should always measure longer over the full length than a new one. A full length measurement is the best way to check the true increase in chain pitch.

Campy does not recommend this method because their chains may show little length increase, even after 10,000km of use. If you make the mistake of using one that long, you'll find extreme wear on the rollers and twice the original clearance between inner and outer plates.

The park tool suggested will not work because the axs rollers are larger in diameter than a normal #40 chain. The roller of an AXS chain are sized to a #41 standard, where the maximum roller diameter is .0065 inch or .165mm larger that a #40 chain.

Try the campy method, where a maximum length is measured between the rollers on two sets of outer plates. You have to know the length of a new chain, then add .75% to get the worn length. The worn length for a Campy chain is 132.6mm. I measured the length of a new AXS chain and got a longer initial length than expected of 131.75, which is greater than a new Campy chain, despite the larger rollers and indicates larger than normal holes in the rollers. The worn measurement for an AXS chain should be about 132.8mm, adding 1mm to the new length.

I plan to check both the full length and the between roller length to see how this chain wears.

A cheap kmc 11.93 chain will increase in overall length very quickly, so it's best to take a full length or at least a 12 inch long measurement.

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Alexbn921
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by Alexbn921

DaveS wrote:
Sat Feb 22, 2020 3:44 pm
A used chain should always measure longer over the full length than a new one. A full length measurement is the best way to check the true increase in chain pitch.

Campy does not recommend this method because their chains may show little length increase, even after 10,000km of use. If you make the mistake of using one that long, you'll find extreme wear on the rollers and twice the original clearance between inner and outer plates.

The park tool suggested will not work because the axs rollers are larger in diameter than a normal #40 chain. The roller of an AXS chain are sized to a #41 standard, where the maximum roller diameter is .0065 inch or .165mm larger that a #40 chain.

Try the campy method, where a maximum length is measured between the rollers on two sets of outer plates. You have to know the length of a new chain, then add .75% to get the worn length. The worn length for a Campy chain is 132.6mm. I measured the length of a new AXS chain and got a longer initial length than expected of 131.75, which is greater than a new Campy chain, despite the larger rollers and indicates larger than normal holes in the rollers. The worn measurement for an AXS chain should be about 132.8mm, adding 1mm to the new length.

I plan to check both the full length and the between roller length to see how this chain wears.

A cheap kmc 11.93 chain will increase in overall length very quickly, so it's best to take a full length or at least a 12 inch long measurement.
Thanks. I broke out the mitutoyo digital caliper and got 131.91-131.96mm. Still have plenty of life left.

TobinHatesYou
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by TobinHatesYou

The Park Tool CC-4 suggested WILL work because it is not measuring the inside-inside distance between rollers. It is measuring inside-outside. While roller diameter has increased, this method isolates out the radius of each individual roller. The only way this chain checker wouldn’t be accurate is if individual rollers wore on the exterior at significantly different rates, which is unlikely. As always, you should measure the chain in multiple locations.

DaveS
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by DaveS

I'd certainly compare the results from a ruler with the park tool, to see if they agree. That's the contention, that the park tool measures true elongation, correct?

Even so, you really need to know how the chain wears before declaring a tool to be appropriate. If the chain behaves like a Campy chain, true elongation is irrelevant because other parts of the chain will be worn out long before .5% true elongation (change in pitch) is ever reached.

With a KMC chain, an elongation measurement works because that's the largest type of wear. The KMC 11.93 elongates at a rate that's at least 5 times faster than a Campy chain.

DaveS
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by DaveS

Alexbn921 wrote:
Sat Feb 22, 2020 1:01 am
TobinHatesYou wrote:
Sat Feb 22, 2020 12:04 am

Pin pitch hasn't changed with SRAM 12spd road. It is still 1/2" between pins. And yes, the tool linked above works with any 1/2" pitch chain.
My Park CC-3.2 dosn't work so I was going old school, but found the chain was short instead of long. Used 2 diffrent rulers too. Measuring the entire chain came up short as well.
I found that too. It would be interesting to know if that was done purposely or if it's a case of accumulative error. I had no problem using the AXS chain with my Campy drivetrain, but each of my two chains only have about 650km on them. I'm alternating 6 chains on two bikes and may bump that up to 8.

TheRich
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by TheRich

dannywin42 wrote:
Sat Feb 22, 2020 12:20 am
I heard on a podcast that the pin diameter is slightly larger than other 11sp and 12sp chains so normal chain checkers wont work, they will read low wear

Sent from my SM-G975F using Tapatalk
Not all chain checkers operate the same so it's pretty important to differentiate between something like the Park CC-2 (with the little flippy measuring thing and the window to read it) and go/no-go gauges like the Park CC-3.2 or .4 or similar from Shimano or others.

What I got out of it was that the go/no-go gauges were stil accurate...please correct me if I'm wrong in using a Shimano TL-CN42. (https://www.google.com/search?q=tl-cn42+shimano)

DaveS
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by DaveS

Old gages were never accurate to start with. They may be accurate enough to satisfy some users, particularly those who don't understand chain wear and claim that chains cost pennies, so tossing them frequently is fine. What they do is add roller wear to actual elongation (change in pitch) to give a mixed reading.

If calipers are used to take the smallest measurement between two pairs of outer links, the AXS chain with it's larger rollers actually measures 0.3mm or .012 inch longer than a standard chain. I get 30.01mm for a Campy chain and 30.31 for the AXS. Taking a longer measurement showed just the opposite, with the AXS chain being a little longer over a 131.75mm length, compared to 131.6mm for a Campy chain. As a percentage, the difference is insignificant at 0.1%.

Whenever I get more wear on an AXS chain, I'll measure both the true elongation and the increase in the roller spacing to see what part of the chain is wearing the most.

gerryc89
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by gerryc89

"And as covered in the chain wear article, SRAM chains do present major issues if using standard chain wear measuring tools. This is directly related to the use of oversized rollers. In fact, common chain tools won’t physically fit into the X01 and XX1-level SRAM chains, even after elongation wear is measured. At least for now, SRAM chains are best measured with backside-to-backside wear tools such as the Pedros’ Chain Checker Plus II and Park Tool CC-4, or better yet, with a pure elongation wear measurement."

It's apparently quite hard to measure the new Sram chains. Great (and detailed!) article here - https://cyclingtips.com/2019/12/the-bes ... cy-tested/

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Alexbn921
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by Alexbn921

I picked up a new red chain today to suport my local shop and it measures 131.8. Old chain is still going strong after 3,200 miles.

by Weenie


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