Something broken in the axle/cassette?

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Something broken in the axle/cassette?

Postby kabukiman » Sun Aug 03, 2008 12:27 am

I'm not totally up-to-date with bicycle terminology so please excuse if I describe the wrong part or my description is confusing.

I have an Avanti Ridge Rider 2005. When peddling normally, changing gears etc appear fine. If i'm in a high gear on the rear derailleur and try and give it some force it sorta of slips like their is something broken within the rear axle. It happens from a standing start or changing gears - if I change gears from low to high and then try and peddle more forcefully it does it. I'll probably take it to my local cycle shop, but it would be nice to get an idea of what it could be.
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by BNA » Sun Aug 03, 2008 12:53 am

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Postby gsxrboy » Sun Aug 03, 2008 12:53 am

Does it happen every time or random? Broken teeth on the gear clusters?

also

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Postby mikesbytes » Sun Aug 03, 2008 7:53 am

Sounds like a worn chain and/or cassette
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Postby Kalgrm » Sun Aug 03, 2008 8:13 am

mikesbytes wrote:Sounds like a worn chain and/or cassette

+1, especially if you have recently put a new chain on without replacing the cassette.

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Postby il padrone » Sun Aug 03, 2008 11:42 am

Yep, sounds just like a worn chain/cassette with a new component fitted. If you change either of the chain or cassette (and sometimes the chainrings at the front) they need to all be changed because they wear together (the spaces between each link/tooth stretch out with the wear). After the drivetrain has been used for a length of time (~3000kms) changing just one part (the chain or the cassette) will lead to mis-matching and the chain will skip. Often it's jst on one or two cogs - the most heavily used, and the smaller cogs wear quicker.

Usually you can use the same chain and cluster for a long time without problems. I've seen a friend ride the same drivetrain until he had broken several teeth off on the cluster :shock: . But if you have been tending to ride a lot of the time in a few cogs, then shifting to a less used cog (like the top gear) will show up the worn chain.

An easy trick to judge wear is to lift the chain at the chainring. A new chain will not lift off. If you can see daylight under the chain it has some wear, lift it to 1/2 the height of a tooth the chain needs replacing, lift it to the full height of the tooth then the chain and cassette will be clapped out.

This is not very scientific. You can do it more accurately by measuring 12" of chain - this will be 12 full links on a new chain as the chain has a 1" pitch. If 12 links measure >12 1/16" the chain is worn and needs to be replaced, but sprockets should be OK. If it's 12 1/8" the chain and sprockets may be too worn for a new chain to mesh correctly and a new cassette will be needed. >12 1/8" you'll need a new cassette for sure, and maybe new chainrings

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Postby bmorey » Sun Aug 03, 2008 1:32 pm

il padrone wrote:An easy trick to judge wear is to lift the chain at the chainring. A new chain will not lift off. If you can see daylight under the chain it has some wear, lift it to 1/2 the height of a tooth the chain needs replacing, lift it to the full height of the tooth then the chain and cassette will be clapped out.



Last week I went to LBS with a broken axle problem and poor shifting. The above is the first thing they did. Result -- the entire drive train was beyond economical repair. I bought a new flat-bar roadie (just the excuse I needed!).

A year ago I replaced a worn chain without replacing the rear cluster. It was awful - worse than just the worn chain on its own.
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Postby nzdans » Sun Aug 03, 2008 4:51 pm

+1 for all of the above, I'm pleased to see folks here know their stuff, nice one!! :D

There is one other thing that can give similar symptoms but it's a long shot; a damaged or siezed link in your chain can be easily found by observing your chain at the rear derailleur while rotating the cranks and pedals backwardsd by hand. If you have dodgy links in your chain they will not pass the rear derailleur jockey wheels (or pulleys) smoothly. If you see this your LBS may be able to repair, if not you're most likely up for at least new chain & cassette.
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