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Old 09-25-09, 02:23 PM   #1
Chacal
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chain skipping on smallest cogs

I know this has been covered here -just curious -

I just replaced my 12-26 cassette with a 12-32 (9 speed)

The 12-26 and the chain were both put on brand new at the same time about 250 miles ago.

The 12-32 came to me on a moderately used 10 year old bike.

The 6 larger cogs seem to work fine with the 53 or 39t chain ring, but neither chain ring works well on the smallest three. the smallest one works the worst, with slight improvement as you shoft down to a larger cog.

I am thinking this is obviously wear on the smaller cogs with less teeth, but could chain slack have anything to do with it? I only took about two links out of the new chain and it is not at all too tight when on the 39x32.

People riding behind me have told me the chain looks way too loose when I am in the outer section of the 12-26 cassette and the 39. I know you shouldn't cross chain, but any thoughts on how shortening the chain another link or two might affect skipping?

Btw this is a non-indexed old DT shift road bike...very small frame, so short chainstays.

Thanks for any help or thoughts.
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Old 09-25-09, 06:02 PM   #2
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Do you know how to measure your chain for proper size?

Quick answer: Wrap chain around two largest sprockets (front and rear) without threading through the RD. Pull tight. Then add at least one full link (two half-links).

(Shimano has a different procedure that works just as well but is more complicated.)

Make your chain the correct length and see how it performs.
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Old 09-25-09, 06:44 PM   #3
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A couple of theories:

1) Do the measurement thing that DMF posted above,
2) Moderately used 10-year old cassette with a brand-new chain typically don't mix. I'd see if you could use the outer cogs from the 12/26 on the 12/32, just because you might have some worn out cogs.
3) Powerlinks or quick links don't like to change cassettes much. If you've got one of those, replace it.
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Old 09-27-09, 01:20 PM   #4
Chacal
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Thanks Guys, the chain is a SRAM Powerlink. I'll probably change the cassette....I was just hoping to get a bike rolling in time for a ride yesterday, but no go.


I'll have to spring for a new wide range cassette; just not in as much of a hurry now.
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Old 09-27-09, 02:03 PM   #5
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yeah I second the old cassette new chain theory. Often a new chain will not work with an old cassette due to the wear you get on both parts. THe teeth on the cassette have probably worn to match an old chain. Chains don't stretch, but the rollers on them wear down on the inside and so they offset on the pin a hair when pulled over the teeth on the sproket.
2 solutions
1. put a couple old chains on till you find one that is worn properly for the cassette-hard to do
2. get a new cassette and a new chain at the same time-more expensive.
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