Tech Mailbag #7: How many times can I reuse a 12-speed master link?

Also: running a worn chain and alternatives to SRAM AXS Flat-Top chains.

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Welcome to the CyclingTips Mailbag column, where you send us your tech questions, and our team of nerds gives you answers. Got a question about wheel and tyre standards? Want to know how to diagnose that weird shifting issue? Wondering where that darn ticking sound is coming from?! Post your question on the CyclingTips Forum using the #askanerd hashtag, or send it to to be featured in an upcoming CT Mailbag column.

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In this week’s Mailbag, we discuss all things related to chains, including re-using master links, chain wear concerns, and SRAM AXS chain compatibility.

From the CyclingTips forum:


Thanks for the advice to date.

I put on a new Ultegra 11 speed chain about 11,500 km ago. According to my Park Tool chain checker, it’s still only around .55 worn! It measured around .1 when new. (The chain checker doesn’t seem faulty, and suggests new chains would start at between .25 and .5)

I’m gentle on my gear and keep the chain clean and lubed. I usually get around 11,000 k from my chains.

I’m happy to keep going with the chain, but the chainrings are now 40,000 k old, and the cassette is 20,000k old. I’m now (very) occasionally getting a sloppy chainring shift.

Any thoughts on the risks of keeping going till shifting deteriorates?


 —Tim Cartwright

Hi Tim,

It sounds to me like you’re using the Park Tool CC-2 which provides such fine measurements. In my experience, this chain checker can be a little hit-and-miss in terms of measurement accuracy. While it’s likely there’s nothing wrong with your measurement, I’d suggest borrowing a second chain checker to compare the wear. 

 Given the usage to date on the rings (which are likely now worn), my advice would be to keep riding the existing chain with the goal to replace the chain, cassette, chainrings, and pulley wheels at the same time. 

You’ll know when this replacement time arrives when you start experiencing skipping in your most-used rear cogs, chainsuck on the front (where the chain is catching onto the ring), or just generally degraded shifting performance. An extremely worn chain can be more susceptible to breakage, but I wouldn’t be too concerned about that given that the measured wear isn’t too extreme. 

 — Dave

Listening to the chain lube podcast, how many times can I pop a master link on and off for both road and mountain bike? I’ve been burned twice on my mountain bike reusing a SRAM Eagle 12-speed master link.

 — An Ha (asked via the VeloClub Slack channel).

The answer to this is certainly somewhat of a grey area. And as you’ve found out, there is a chance for product failure if you ignore the company warnings. 

The likes of Shimano and SRAM state that their 11- and 12-speed chain links are single-use only, and once you open them, they need to be replaced. 

However, there are countless examples of people having no issues by re-using these. As covered in a previous article focusing on all things master links (aka quick links), the advice is to use them until they no longer provide noticeable resistance in opening or closing. In my experience with 12-speed links, this is 3-4 uses. After that, I start to get nervous.

Alternatively, you can mix-and-match brands of master links. KMC offers single-use links which may be more affordable than some others. Connex links, while very expensive, can be opened and closed infinitely as the design relies on plate shape for retention as opposed to a tolerance fit. And my go-to is YBN, which offer well-priced 12-speed links which are claimed to be good for re-using up to five times each. 

One thing to watch for is that the 12-speed links are pretty narrow and it’s not all that difficult to install them wrongly where only one side of the link is engaged with a pin. Add a freshly set solid wax into the mix and this issue is only more likely to occur. It’s always a good idea to closely inspect a master link to ensure both sides are fully engaged. This is why I prefer using a master link plier with the ability to close links (such as the Shimano TL-CN10), as it gives me a free hand to squeeze the link together while I close it. 

As a final note, broken chains can lead to pretty serious crashes and injury, so this is one area where the advice above must be used at your own risk. If reusing a master link makes you nervous, then it’s best to follow the guidelines of the manufacturer.

— Dave

From the CyclingTips forum:

Is anyone using a KMC X12 chain on any of SRAM’s AXS road groupsets?

I’m looking for an alternative to the SRAM Flat Top chains on an upcoming Red AXS build and have had great performance from KMC chains on other groupsets of 11 speed and below. The KMC chain is not of the Flat Top design.

— Brycles

This is an interesting one. SRAM AXS 12-speed road does indeed use a chain with a unique flat top plate shape, but really the thing that differentiates it is the unique oversized roller that the cog tooth profiles are then designed to match. SRAM maintains that only its chain should be used and it controls that side of things quite fiercely on the Original Equipment (OE) side as far as complete bike specifications go. 

That said, KMC is indeed claiming that its 12-speed chains will work with all common 12-speed drivetrains, including SRAM AXS road. Similarly, Wippermann’s Connext 12-speed chains appear to make the same claim. Here’s what a representative from KMC had to say on the matter. 

“All KMC 12s chains, including X12 and e12 Series, are compatible on all 12s systems including SRAM AXS Road and Eagle.

SRAM’s larger roller is to fill their very slightly larger tooth roller seat for higher efficiency of the roller transition through the seat. Our rollers are regular size and therefore simply transfer through their seat a little more. We’re still showing similar high efficiency.”

I personally haven’t tried this combination (yet) and so can’t speak to shift performance or durability. Similarly, Zero Friction Cycling, our usual resource for wear-based drivetrain testing, hasn’t yet done such a test to know whether using a chain with a regular roller size increases tooth wear on AXS road cassettes and rings (I hypothesise that it does). This is certainly a topic that I hope to have a more definitive answer for in future.

 — Dave

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