Why exactly is my new KMC joiner link non reusable?

[uart]

I've just bought a couple of new KMC chains, and the packaging on the included joiner link (missing link) is at pains to point out that they are "non reusable".

Having just successfully clipped them together and popped them apart (twice) to see how they work, I'm wondering why exactly they are non reusable.

[Duck!]

Because opening them wears down the locking nodes, which then makes a less secure join and increased risk of popping open.

[uart]

Because opening them wears down the locking nodes, which then makes a less secure join and increased risk of popping open.

Ok thanks, that's kind of what I was thinking.

Trust me though, they where still plenty stiff to pop open even on the second try, so I think a limited amount of reuse is going to work just fine.

[queequeg]

I've just bought a couple of new KMC chains, and the packaging on the included joiner link (missing link) is at pains to point out that they are "non reusable".

Having just successfully clipped them together and popped them apart (twice) to see how they work, I'm wondering why exactly they are non reusable.

You may reuse them on the chain you have installed them on. You should not take a used link and put it on another chain.

[Tim]

You may reuse them on the chain you have installed them on. You should not take a used link and put it on another chain.

Not sure this is absolutely correct but it's what I do.
Each chain comes off the bike at 1000km intervals on rotation with another chain. Each chain is removed and then refitted 5 times ie. each chain and link lasts me 5000km's.
No problems so far.
10 speed KMC links are reusable, 11 speed non.

Pinch the side plates together (inwards) with your fingers and then open them with the tool (whilst still pinching). The pinching loosens the connection and the link opens easier.

[queequeg]

You may reuse them on the chain you have installed them on. You should not take a used link and put it on another chain.

Not sure this is absolutely correct but it's what I do.
Each chain comes off the bike at 1000km intervals on rotation with another chain. Each chain is removed and then refitted 5 times ie. each chain and link lasts me 5000km's.
No problems so far.
10 speed KMC links are reusable, 11 speed non.

Pinch the side plates together (inwards) with your fingers and then open them with the tool (whilst still pinching). The pinching loosens the connection and the link opens easier.

Straight from the KMC Site: "Always use a new Missing Link when fitting a new chain".

As for whether they are reusable on the same chain in the meantime, their official position is no, and you may or may not be able to get the link off with just your hands out on the road. However, as long as the link is not damaged, and you don't carry an old link across to a new chain, you should be ok. It would also depend how often you are taking your chain off, but given the cost of the Missing Links, I don't make a habit of just putting a new one on for the sake of it, but I do check it carefully as a poorly fitting link is likely to result in a broken chain.

[RonK]

I've just bought a couple of new KMC chains, and the packaging on the included joiner link (missing link) is at pains to point out that they are "non reusable".

Having just successfully clipped them together and popped them apart (twice) to see how they work, I'm wondering why exactly they are non reusable.

You may reuse them on the chain you have installed them on. You should not take a used link and put it on another chain.

Yes, that is how I choose to interpret for Sram Powerlock links too.

[Duck!]

I've just bought a couple of new KMC chains, and the packaging on the included joiner link (missing link) is at pains to point out that they are "non reusable".

Having just successfully clipped them together and popped them apart (twice) to see how they work, I'm wondering why exactly they are non reusable.

You may reuse them on the chain you have installed them on. You should not take a used link and put it on another chain.

Yes, that is how I choose to interpret for Sram Powerlock links too.

SRAM's wording is quite clear - the link is not intended to be undone. 8 & 9-sp. links are intended to be used several times over the life of one chain, 10+ are not. KMC do both multi-use (which like SRAM 8 &9) are to be discarded when the chain is done, and single use which are exactly that.

Even if they don't fail, repeatedly opening and closing the link increases wear on the link, so you end up with that link longer than every other link in the chain, which leads to rough running, which you'll feel as a bump or clunk in the drivetrain every time the link goes around the cassette.

[foo on patrol]

Never had a problem reusing the links and that's with different chains.

Foo

[uart]

Even if they don't fail, repeatedly opening and closing the link increases wear on the link, so you end up with that link longer than every other link in the chain

I accept that they might get slightly looser to fit with repeated opening and closing, but I do doubt that it would have any significant effect on the link's length.

To increase the effective length of the link you would need to wear the end stop position of the slot in the side wall of the link. Any effect on the length of the slot from opening and closing is going to be totally negligible compared to when the chain is in use with your full weight on it.

[eeksll]

i use both 9,10 and 11 speed links.

on both the 9 and 10 speed chians, on my parktool go/no go ruler, when the link is part of the measurement, it registers as "worn" before the rest of the chain. I don't remove my links often, maybe twice in the chain life.

Both my current 9 and 10 speed chains are at this point, 0.5 almost falls in for the rest of the chain, but falls in easily when the chain link is in the middle. I haven't opened the link from new on these 2 chains.

the 11 speed is campag and parts are expensive so I don't let the chain get too worn before swapping.

edit: i use new links with new chains and I also don't notice anything odd with this longer link.

[Duck!]

on both the 9 and 10 speed chians, on my parktool go/no go ruler, when the link is part of the measurement, it registers as "worn" before the rest of the chain.

I have also observed this, on several brands of links, so it's not an isolated occurrence. I was first alerted to joining link wear with Shimano's early quick links (which were pretty dreadful to be blunt), introduced with the 7900-series Dura-Ace 10-sp. chain; I had a customer complain of a weird clunk in the drivetrain, out of synch with the crank rotation. After much test riding, head scratching & investigating I thought to measure chain wear at different points of the chain, with and without the joiner in the measured span. Sure enough, measuring the chain excluding the joining link showed a very healthy chain. Spin around & include the link in the measured span, and it showed as badly worn. That's a hell of a lot of wear in one link! Now those Shimano links were considerably worse than other joiners, but I've observed the same accelerated wear in every other brand of quick joining link I've worked with to some degree. Even on links that have never been opened.

So from my observations, I conclude that, even if manufacturers suggest it's OK with some models, joining links should not be used for the whole life of one chain .

[Tim]

11 speed KMC Missing Links are expensive from the usual local and O/S suppliers.
I've bought them at around half the price from eBay, Taiwan source (I think) and they have been genuine parts (I think and hope).
Been using them for 2-3 years and no problems.

Re the above photo instructions.
9 and 10 speed (KMC) can be opened by hand. As I mentioned earlier, pinch the side plates together and they'll disassemble fairly easily without a tool.
11 speed snap closed and need a tool to open. It still helps pinching the plates first.

[eeksll]

11 speed KMC Missing Links are expensive from the usual local and O/S suppliers.
I've bought them at around half the price from eBay, Taiwan source (I think) and they have been genuine parts (I think and hope).
Been using them for 2-3 years and no problems.

I got mine off ebay as well.

[peter]

While looking for spare links, I've noticed that some KMC missing links end with R, I guess it means reusable. The non-R links clearly state that they are not reusable, the R links don't (imply reusable).

What makes the R links reusable? Stiffer and more durable material?

[trailgumby]

I've only ever had one KMC 10-speed chain come apart at the quick-link, and that was just recently after about 5-6 years of constant re-use in all conditions, including gritty off-road riding. Supposedly they are single use only as well. I have experienced no discernable lengthening relative to the rest of the chain.

New links are a PITA to fit, usually requiring dedicated tools you wouldn't carry on a ride, so I prefer to avoid them if humanly possible. The brand-new replacement link I fitted at McCarr's Creek road in May took about 10 minutes to finally manipulate into locking into place by wiggling it around with an Allen key. 11 and 12 speed are even worse, so I'm not sure how that's going to go if I ever break a chain in the middle of nowhere when it's dark and cold and I'm out of phone range.

I use 3 chains in rotation on each of my bikes, as this maximises the wear I get out of the cassette and chainrings. Doing this means removing the chain from the bike each time it needs cleaning. This is the second set of 3 chains on this particular bike. The rings and cassette are now finally at a point where they need replacing at 8 and 9 years old respectively, after about 50,000 kilometres.

I will likely keep re-using quick links now that I am about to join the current decade with 11 speed (road) and 12 speed (MTB) chains.

[MichaelB]

This has been an interesting post !!

Now that I am waxing my chains (and did it before as well, but removed the chain less frequently), the quick link is removed multiple times in the chains life.

I've never had a problem, including using a 10sp KMC link on 11sp KMC chains.

When I'm removing the chains , I keep the quick links with their respective chains (as advised by Duck!).

I think the 'non-reuseable' bit is more of a liability/ass-covering scenario.

[Duck!]

New links are a PITA to fit, usually requiring dedicated tools you wouldn't carry on a ride, so I prefer to avoid them if humanly possible. The brand-new replacement link I fitted at McCarr's Creek road in May took about 10 minutes to finally manipulate into locking into place by wiggling it around with an Allen key. 11 and 12 speed are even worse, so I'm not sure how that's going to go if I ever break a chain in the middle of nowhere when it's dark and cold and I'm out of phone range.

You don't need any tools to join even the tightest link. With the link loosely engaged, rotate the link to the top span of the chain, hold the rear brake & stand on the pedal.

[peter]

There are also levers now that double up as quick link remover/connector, such as Topeak Power Lever X (currently out of stock locally).

Is there still a need to carry spare pins? Or just use quick links instead (but still need to bring a chain tool)?

[open roader]

Keep the same link with the same chain - has worked for me on a maybe a couple of dozen chains.

I recently purchased a used 9sp. bike which required a new chain. New chain on hand but no fresh link for a few days. Fitted the old link for test riding purposes (200m ride) and noticed how sloppy the old link was running over the chain rings compared to the new one when I lubed it up and inspected it all up close.

It figures :- the older links wear down similarly to older chains.

[trailgumby]

New links are a PITA to fit, usually requiring dedicated tools you wouldn't carry on a ride, so I prefer to avoid them if humanly possible. The brand-new replacement link I fitted at McCarr's Creek road in May took about 10 minutes to finally manipulate into locking into place by wiggling it around with an Allen key. 11 and 12 speed are even worse, so I'm not sure how that's going to go if I ever break a chain in the middle of nowhere when it's dark and cold and I'm out of phone range.

You don't need any tools to join even the tightest link. With the link loosely engaged, rotate the link to the top span of the chain, hold the rear brake & stand on the pedal.

Worked well for 9-speed but on 10-speed it has never worked for me. However, on multiple occasions, the link has parted company and one or both link halves have been flung and lost. Maybe I'm doing something wrong but at the bottom of a long climb and 20km from home I wasn't taking the chance.

Stomping on the pedal with my full 82kg with the brake locked failed with 11 and 12 speed and it's a punish even with proper BBB link pliers.

I'm not disputing your experience, it's just that my experience to date has not matched the convention on what's supposed to happen.

[Duck!]

Shimano 11 & 12-sp. links are the tightest I've met, but the brake & stomp method has never failed, and I'm around 70kg. They are a bit fussy with getting the grooves & slots aligned, which might be where you're having problems. Other links lock in OK with hand pressure on the crank in the same basic method.

[RonK]

You may reuse them on the chain you have installed them on. You should not take a used link and put it on another chain.

Yes, that's how I choose to interpret what I consider to be a somewhat ambiguous statement.

Quite clearly these links can be opened and closed multiple times and still close securely.

More likely it's an attempt to legally indemnify themselves in case of a failure.

[peter]

KMC lists specific reusable links, they are not always compatible with non-reusable links suggests that there are differences.

[peter]

Okay, just found more information, the different between reusable and non-reusable links is the latch design. Makes sense, ebike chains are stronger and therefore require the latch for extra security, it's the latch that makes it non-reusable. Non-ebike chains don't really matter, they don't need the latch even if compromised.