Sram Chains

ben123
ben123 Posts: 10
edited June 2015 in MTB workshop & tech
Hi folks,
I was removing some links from a sram powerlink chain PC-1031 just now with a chain splitting tool, and I noticed that the pin I removed 'popped' out rather than 'slid' out. I then saw that there had been a tiny (approx 0.2mm thinkness) ring of metal, a bit like a continuous circlip, that was round the end of the pin apparently holding it to the outside of the link plate.
Does anyone know what this is?
I doubt i could get it back in were it came from if I needed to add a link back in. Are sram chains remove link only?
Thanks guys.

Comments

  • Chunkers1980
    Chunkers1980 Posts: 8,035
    Can't visualise what's happened there.

    But SRAM chains should use quick links to join them, so you might need 2 to build it back up. And SRAM power locks are one use only, so I use the KMC version.
  • cooldad
    cooldad Posts: 32,599
    You need to use a missing link/powerlink/whatever they call them.
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  • warpcow
    warpcow Posts: 1,448
    I always get those little rings stuck on the end of the chain-breaker. I'd just assumed it was from where the outer plate may have deformed a little when the pin was originally pressed in.

    Found someone who seems to corroborate that here: http://www.tokyocycle.com/bbs/threads/shortening-chain.2518/#post-30054 (very last bit of the post)
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  • ben123
    ben123 Posts: 10
    Cool. Thanks warpcow. I'm willing to accept the explanation given in the link. the tiny ring is a sliver of link plate material.
    I spent literally 3 hours trying to get the power link apart the first time. You get the hang of it though.
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    Because it was a powerlock and one use only?
  • taffygriffiths
    taffygriffiths Posts: 186
    The pins on a lot of chains are mushroomed over on the ends to contain the plates

    When you push the pin out, you get a lot of resistance then a big crack. The pin then comes out easily.

    That crack is the mushroomed lip of the pin shearing off. And that is what leaves you with that tiny ring of steel.

    Look at both ends of the pin and you will see the difference.

    The times that I've had to re use that pin, the chain has always failed shorty afterwards at that exact location. There's not enough to hold the outer plates together and ultimately, one plate will slide off the pin, and presto... Snapped chain.

    Some chains I've seen re-used fine, but most of the shimano and KMC ones I've used have this riveted pin design.

    I carry a few powerlinks in my bag now host incase!

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