KMC Chain - Broken

rockmount
rockmount Posts: 761
edited June 2010 in Workshop
On the way home tonight, my KMC 10sp chain snapped. I had just stood on the pedals to start a bit of a climb, and I ended up head first in the road :( I have only had the chain since the end of November, and it only has a couple of hundred miles ... Has anyone else had similar, I wouldn't like to do that too often, its a bit dangerous, not to mention a right pain in the ass :evil:
.. who said that, internet forum people ?
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Comments

  • aarw
    aarw Posts: 448
    where on the chain did it give way?
  • Vivid
    Vivid Posts: 267
    Sounds like a manufacturers error or less you damaged the chain when fitting?

    Like above, where did it brake?
  • redddraggon
    redddraggon Posts: 10,862
    Same happened to me just over a week ago, except it happened when I started sprinting @ ~25mph

    Chain snapped across a plate, and it was definitely installed right. Not that old - maybe 400miles

    Ended up ripping all my kit, putting holes in both my knees and both my elbows, wrote off my helmet, and badly scratched shifters.
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  • Kléber
    Kléber Posts: 6,842
    Chains break but JRA (just riding along) doesn't exist, there will be a reason, whether you fitted it badly or there was a problem in the factory. I've used KMC 10s chains with no problems... so far.
  • on-yer-bike
    on-yer-bike Posts: 2,974
    How can you install a chain wrong so that it might snap?

    I had the top £45 KMC chain and one link stopped rotating for what appeared to be no reason, somehow it must have got damaged. The night before I took the rear wheel out, could it have been then?
    Pegoretti
    Colnago
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  • jeepie
    jeepie Posts: 497
    Mine broke at the quick release link after I'd taken it off using the link and cleaned it....I pondered about this and thought that maybe there was a connection....not sure....
  • rockmount
    rockmount Posts: 761
    edited March 2009
    Been away, and just managed to have a look at the chain ... One link broken allowed the chain to part. Two other links cracked, looks like this chain may have been defective.
    .. who said that, internet forum people ?
  • brucey72
    brucey72 Posts: 1,086
    rockmount wrote:
    Been away, and just managed to have a look at the chain ... One link broken allowed the chain to part. Two other links cracked, looks like this chain may have been defective. I don't know if I'd be keen to use KMC in future !! I may take it into work and do a failure analysis on it..
    KMC1.jpg

    KMC2.jpg

    That is exactly what happened to my KMC chain a couple of weeks ago!!

    Mine snapped when pulling away from a junction which was really scary. I put a speedlink in to get home where on inspection I also found two of the links cracked in exactly the same way as yours. My chain had done about 500 miles.

    I suspect its a manufacturing problem but as my chain was binned immediately, its too late to get in touch with KMC
  • crankycrank
    crankycrank Posts: 1,830
    There is definitely some defect in that chain. Unless maybe you have been using it to propel your car? I don't think I've ever seen a bike chain with more than one link break like that. Get an exchange or refund.
  • pud77
    pud77 Posts: 144
    crankycrank wrote:
    There is definitely some defect in that chain. Unless maybe you have been using it to propel your car? I don't think I've ever seen a bike chain with more than one link break like that. Get an exchange or refund.
    Totally agree. Definitely a manufacturing defect. Doesn't inspire confidence at all :?
  • ugo.santalucia
    ugo.santalucia Posts: 28,336
    As a very general rule, which might or might not apply to the specific case, all these boutique stuff are not as good as the original parts made by Shimano or Campagnolo. I have no experience with SRAM, so I can't talk for them. Every time I bought something which wasn't S&C I then reverted to the original.
    Brake pads for example, I bought once these salmon Koolstop, as everybody was praising them so much, I couldn't even fit them in the cartriges without opening completely the calipers, which resulted in a ridiculous braking action, slow and ineffective.

    Judging by the pictures, it's clearly a faulty unit, who knows how many more are around. Engraving the KMC logo on the links might make them look good, but certainly doesn't make them stronger
    left the forum March 2023
  • Simon Notley
    Simon Notley Posts: 1,263
    Don't KMC make 'Shimano' chains anyway, so changing brand may not be the answer?

    I would certainly contact KMC to let them know about the defect, and the seller for a refund...
  • John.T
    John.T Posts: 3,698
    Brake pads for example, I bought once these salmon Koolstop, as everybody was praising them so much, I couldn't even fit them in the cartriges without opening completely the calipers, which resulted in a ridiculous braking action, slow and ineffective.
    I have had several sets and they all fit straight in. I only had to reset the adjuster. Using Shimano Ultegra brakes.
    Judging by the pictures, it's clearly a faulty unit, who knows how many more are around. Engraving the KMC logo on the links might make them look good, but certainly doesn't make them stronger
    Definitely faulty but the engraving has nothing to do with it. Not one crack is across that.
    My Fleet.
  • ugo.santalucia
    ugo.santalucia Posts: 28,336
    John.T wrote:
    Brake pads for example, I bought once these salmon Koolstop, as everybody was praising them so much, I couldn't even fit them in the cartriges without opening completely the calipers, which resulted in a ridiculous braking action, slow and ineffective.
    I have had several sets and they all fit straight in. I only had to reset the adjuster. Using Shimano Ultegra brakes.
    Judging by the pictures, it's clearly a faulty unit, who knows how many more are around. Engraving the KMC logo on the links might make them look good, but certainly doesn't make them stronger
    Definitely faulty but the engraving has nothing to do with it. Not one crack is across that.

    No, it looks like the steel they're using is too hard, it brakes around the pin and in a consistent way, probably the fracture is initiated by the stress induced by the pin insertion during the manufacturing. The fracture itself looks quite brittle, there is no elongation, in the case of steel, is typical of fatigue, which for a chain makes sense.
    All in all it could be a recurrent problem and it doesn't have anything to do with maintenance or use, just wrong steel for the job. I wouldn't be surprised at all if they used that steel because it looks better or it's more corrosion resistant.
    A good chain must rust if left in the wet, I would get suspicious if it doesn't.
    left the forum March 2023
  • crankman
    crankman Posts: 3
    I was just about to replace a slightly worn Campag C10 chain with a KMC X10 L silver before reading this. Definitely looks like a manufacturing fault. Brucey72 & Reddragon, may I ask what the specific model KMC you each were running? I am wondering if the weak outer plates are limited to one KMC model.

    I've run Sedis/Sachs/Sram chains for years without incident (only recently started using alternatives). Hope to keep it that way.
    For every thing there is a season ...
  • rockmount
    rockmount Posts: 761
    edited March 2009
    I reckon it would be worthwhile checking if you have a KMC chain.
    .. who said that, internet forum people ?
  • redddraggon
    redddraggon Posts: 10,862
    Well I've just had my second KMC chain go in 3 weeks- three plates cracked, luckily I noticed the symptoms before I stomped out of the saddle and crashed this time. Managed to get home and swapped the chain for a spare gold KMC - hopefully of a different batch :?

    Definitely a dodgy batch......pictures up soon....
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  • redddraggon
    redddraggon Posts: 10,862
    3336041638_a8d04ab98e.jpg
    I like bikes...

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  • redddraggon
    redddraggon Posts: 10,862
    3335209435_e8d241fe3a.jpg
    I like bikes...

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  • cougie
    cougie Posts: 22,512
    Any chance of anyone at BikeRadar flagging this with KMC ? Something odd is going on here >?
  • dodgy
    dodgy Posts: 2,890
    Very worrying, I think once you've broken a couple like that you lose faith with the brand. Touch wood, only ever had one broken Shimano chain in 20 odd years.
  • angryasian
    angryasian Posts: 27
    Hi all,

    I would agree that something appears amiss here. I've sent a message to my contact at KMC to see if they'd be able to offer a response. I'll post something once I hear back.

    James Huang
    Technical Editor
    BikeRadar.com
    Cyclingnews.com
    James Huang
    Technical Editor
    BikeRadar.com
    Cyclingnews.com
  • cougie
    cougie Posts: 22,512
    Cheers James !
  • dennisn
    dennisn Posts: 10,601
    This post does bring out a really good idea, that at the very least myself and probably a few others have ignored. TAKE A GOOD LOOK AT YOUR CHAIN EVERY WEEK OF SO.
    See if you can spot anything abnormal. I would cast my vote with the possibility that ANY
    brand and or price range of chain is subject to breaking. A lot of small parts fitted together
    can add up to problems. I'm planning on making chain inspection a weekly thing. How long can it take? 10 minutes? It's in my plan from now on. Thanks for making me just a little bit paranoid(in a good way) about chains.

    Dennis Noward
  • bikeforever
    bikeforever Posts: 17
    rockmount wrote:
    On the way home tonight, my KMC 10sp chain snapped. I had just stood on the pedals to start a bit of a climb, and I ended up head first in the road :( I have only had the chain since the end of November, and it only has a couple of hundred miles ... Has anyone else had similar, I wouldn't like to do that too often, its a bit dangerous, not to mention a right pain in the ass :evil:

    Hi Rockmount,

    Is it possible to give me your email in order to contact you directly about the problem? Please advise. Thank you.
  • shane515
    shane515 Posts: 139
    Hello all

    Dont know if I am asking someone to commit a cardinal sin here but can those that have experienced the problem post where/when they got their KMC chains. Its just that the kids have got me a new KMC 10 Speed Chain for my birthday, it currently sits under one of thier beds :wink: but I am now concerned that it maybe already damaged and time is ticking away when it should be returned.

    Shane
  • GF22
    GF22 Posts: 67
    I have just seen this topic and am amazed (and frustrated!!). About three weeks ago, I was out on a ride with a friend and about 20 miles into it, faced with a small incline, I pushed through the pedals (still seated) and the next minute, I heard the noise I associate with my chain coming off and lost all resistance when pedalling.

    I got off the bike and, sure enough, the chain had come off the chainset and, as I attempted to put it back on, my friend noticed something sticking out of the chain. Upon closer inspection, a link had snapped on one side in exactly the same way as described in this topic.

    I was fairly surprised at this and, unfortunately, threw the chain out once I got home, so have to evidence to prove this.

    It goes without saying I was shocked to read this topic and, worryingly, I have just purchased two more KMC chains and am worried about their robustness now!
  • don key
    don key Posts: 494
    I bought two two weeks ago, one is perfect, still in the bag, the other has taken a hammerimng, I looked at some of it with the magnifying glass and it's Ok , I will check tomorrow the rest as it is on the stairs and noise is a problem.
  • Flambes
    Flambes Posts: 191
    This happened to me 2 weeks ago, was going up a 20% incline when the chain came off.
    On inspection, 2 of the plates had snapped, must have been at different times, but I didn't notice.
    This was a 10 speed Dura-Ace chain.
    When I took the chain off, I just put it down to wear as the moment across the plane perpendicular to the rotation of the links was huge!
    Has been on my bike 2 winters though!
    Weather info: http://www.staydry.me.uk
  • robbarker
    robbarker Posts: 1,367
    Kléber wrote:
    Chains break but JRA (just riding along) doesn't exist, there will be a reason, whether you fitted it badly or there was a problem in the factory. I've used KMC 10s chains with no problems... so far.

    I disgagree - I've pulled a 10 speed chain apart standing on the pedals, the break being at a normal link away from the "joint". I don't think they're strong enough personally, we should have stopped at 8 speed and 3/32"!

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