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Thread: Chain stretch

  1. #1
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    New question here. Chain stretch

    I've heard different schools of thought regarding chain stretch on SS's. Some say to just let it go and replace the chain, cog & ring all at once. I've always been a proponent of frequent chain changes to save my cassettes and rings on my geared bikes. I usually change the chain as soon as it shows any measureable stretch, on one of those Park feeler guage things. All was fine, until I just put on my 3rd chain and found my drivetrain made a horrible noise under power. The King stainless cog looks good, but the original Truvativ ring looked fried, so I replaced it. It still makes the noise, but not as loud. Will it just wear together or what?

    Thanks!

  2. #2
    Known Mountainbiker
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    mumbo-jumbo

    With a streched chain, the chainring will take most of the abuse, assuming it's aluminum, and then the steel cog. The chainring will wear regardless of how often you slap a new chain on. It's a SS thing.

    I ride with a steel kingcog, a 1/8 bmx chain and fsa ring. In two years of Oregon singletrack; I've gone thru three rings, six chains and I'm still on the original kingcog.

    I think it will vary per person but IMO, It's a SS and you got about 60 bucks (average) worth of parts for the drivetrain, $55 for the cog and ring and 5 for the chain. Allowing the chain to go bad will trash the other two. No reason to let that happen unless you're rich and have time to wait for a backordered KingCog.

    Also, a fresh chain on used ring and cog will make noise. The quick way I check wear on my ring is to hold the crank still and try to slide the chain in the teeth. (back off Sparty)
    Lots-o-movement not good. But really, you can see wear on a ring.

    caz
    I am a Mountain Biker therefore I am late

  3. #3
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    i use, and recommend that you slap on, one of the surly steel chainrings.

    very little wear over lots of miles.

  4. #4
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    the chain is made of steel, most cogs and chainrings are aluminum. so, it goes without saying that the aluminum will wear much faster than the steel. if you can make all the parts on your drivetrain steel, you should get much more mileage out of it.

    as far as chain stretch, the chain doesnt actually stretch. i will let sheldon brown explain it to us.

    http://www.sheldonbrown.com/chains.html



    "Cyclists often speak of chain "stretch", as if the side plates of an old chain were pulled out of shape by the repeated stresses of pedaling. This is not actually how chains elongate. The major cause of chain "stretch" is wearing away of the metal where the rivet rotates inside of the bushing (or the "bushing" part of the inside plate) as the chain links flex and straighten as the chain goes onto and off of the sprockets. If you take apart an old, worn out chain, you can easily see the little notches worn into the sides of the rivets by the inside edges of the bushings."
    Last edited by dirtdirt223; 02-01-2007 at 07:23 PM.

  5. #5
    CB2
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    I run a WI freewheel, and since it cost $70, I'm going to change my chain before it is too worn. Fortunately, when my axle is at it's furthest position back in my semi vertical dropouts, my chain will be too loose and I know it's time to change it.

  6. #6
    pvd
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    chains don't stretch. they wear.

  7. #7
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    New question here. wait...what?

    Quote Originally Posted by pvd
    chains don't stretch. they wear.

    How then does an old chain when laid next to a new chain and both being the same number of links become longer. There is no way that wear could account for that!
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  8. #8
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    Quote Originally Posted by rockcrusher
    How then does an old chain when laid next to a new chain and both being the same number of links become longer. There is no way that wear could account for that!
    A small amount of wear at each link (x50+ links) can add up to a longer chain. My worn chain is usually only a few mm longer than my new chain, but I change the chain a few times a year.

  9. #9
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    oh, I get it. Wear in the bushing lengthens the chain incrementally per bushing. Makes sense. Thanks.
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