If it works don't fix it- Mtbr.com
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  1. #1
    Retro Grouch
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    If it works don't fix it

    A while back I added this way cool Shimano cn-nxo1 on my Rocklobster; this is the chain Trek uses on their Travis' 69 SS. Now I'm running a pretty worn chainring, but I've never had any chain problems before with KMC z610hx (3/32) chain. Yet the first ride I had on this chain, I was coasting down a fast rocky singletrack and it derailed. I chalked it up to too loose a chain and after a couple more rides, I hung it up for the winter and have been riding my SASS. Anyway, today I took down the Rocklobster and went for a ride in Nisene Marks Park (an unbelievable day were there 3-4 groups of other riders, all faster than me and all on singlespeeds). Anyway I was coasting down the fire road, took a very rutted corner very hard and fast and snap! the chain popped off; I don't even remember peddling, but I might have been positioning the pedals. Anyway I've come to the conclusion there is something about the design of this chain, that causes it to derail with less than perfect chainrings. I've switched it out and with a z520hx (1/8") and plan on taking it down the same singletrack to confirm my suspicions. Any comment on why this chain won't stay put?
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  2. #2
    PSYCHOLUST
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    This is forum stuff at it's best....... YOU spend your money then warn the rest of us away from stuff that just isn't worth it.
    Thanks

    If, like TRAVIS , you got PAID to rock some spaceage chain design, then maybe.

  3. #3
    Out spokin'
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    Dunno but it's sure got a purdy mouth.

    --Sparty
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    We get old because we quit riding.

  4. #4
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    It's a 1/8" chain. They derail easier with 3/32" chainrings and cogs. But I guess you can confirm that when you run the Z520hx.

  5. #5
    Retro Grouch
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    Quote Originally Posted by itsdoable
    It's a 1/8" chain. They derail easier with 3/32" chainrings and cogs. But I guess you can confirm that when you run the Z520hx.
    I have never had an issue using an 1/8" chain on 3/32 chainrings/cogs. My guess is the profile of the plates allow the plates to ride up on the machined ridge as well as the ledge created by the chain wear and derail (sorry, it would have been helpful to show this photo to begin with; the chainring has more wear than when this picture was taken).
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  6. #6
    Birthday Collector
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    Brad - my guess is that you are partially correct in that a combination of the 1/8" wide bushings, allows some lateral "slop" across the tooth face, the ovalized profile of the side plate can potentially more easily hit that ridge and get a bit of lift... Also, you have a worn ring, that with a new chain has the potential to put a tooth under a bushing instead of in between them. With all of these things going against you - I'd suggest getting a new chainring (and potentially a cog) and then running a proven chain. If you are going to stick with 3/32" rings and cogs - use that width of chain. Make sure your rear cog is in good shape - or reverse it if you can to have a "new" tooth face against the new chain. If it is worn much, all the new stuff in the world won't keep your chain from potentially jumping off of that too. That Shimano chain in the pic is one strange-looking piece of bike bling. Any pic of the ring in it's current state of wear?
    R.I.P. Corky 10/97-4/09
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  7. #7
    Retro Grouch
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    Quote Originally Posted by ATBScott
    Brad - my guess is that you are partially correct in that a combination of the 1/8" wide bushings, allows some lateral "slop" across the tooth face, the ovalized profile of the side plate can potentially more easily hit that ridge and get a bit of lift... Also, you have a worn ring, that with a new chain has the potential to put a tooth under a bushing instead of in between them. With all of these things going against you - I'd suggest getting a new chainring (and potentially a cog) and then running a proven chain. If you are going to stick with 3/32" rings and cogs - use that width of chain. Make sure your rear cog is in good shape - or reverse it if you can to have a "new" tooth face against the new chain. If it is worn much, all the new stuff in the world won't keep your chain from potentially jumping off of that too. That Shimano chain in the pic is one strange-looking piece of bike bling. Any pic of the ring in it's current state of wear?
    I took a new picture to show the current state of wear. I since installed the z510HX chain and went for a ride today on some very rutted and rooted trails and the chain stayed on without even a click.

    I want to hold on to the chain ring for a little longer, until I know for sure it's the problem; it's a research project of mine. As I said before, I have never found a 1/8" chain to be a problem on a 3/32 drive train; at least until now. I'm thinking the ovalized profile is the real culprit, but I want some more rides to be certain.
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    Just one more rep and I get the toaster!

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