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Old 04-01-09, 08:55 AM
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Mr. Underbridge
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Join Date: Mar 2007
Location: Reston, VA
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Bikes: 2003 Giant OCR2

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Originally Posted by pgoat
*I understand how the 12-21 cassette I used from late 07 to early 09 - probably about 2000 miles - could have worn from the old chain. But would the original new 13-23 cassette also be too worn for a new chain? As I mentioned, it has maybe 500 miles or less on it, albeit with a different chain, but one that started out new together.
Is it possible that running the new cassette on the new chain wore it out pretty quickly? It's possible that by the time you did your test on the less-worn cassette, the chain had mated to the worn cassette.

Originally Posted by pgoat
*would the fact that it is a SRAM chain on a Shimano Hyperglide cassette matter?
As long as you got the correct chain, it shouldn't.

Originally Posted by pgoat
*Would the length of the chain have anything to do with this? I was wondering if shortening it would make a difference. I should point out I had no skipping issues until a month or so ago, so I guess that isn't likely. btw, I shortened the new chain I just put on to match the new chain installed in 2007...no idea whether the shop used my old original chain with the 13-30 cassette as a guide or resized big/big, etc.
Possible. If the chain's too long, then the derailer might have to open too far to provide tension for the chain. When using the small cogs, possibly combined with a B-screw that's backed out too far, you could end up with fewer chain links contacting the cogs than you'd like. That could make skipping more likely. More importantly, it could also accelerate wear of the drivetrain. You could adjust the B-screw and shorten the chain to an appropriate length to see if it minimizes the effect. I go with enough chain to wrap around the big-big combo, plus two links. However, there's a good chance that you've done damage to the new parts in the interim.

Originally Posted by pgoat
*Finally, while I have no problem spending the money on a new cassette, I hate to do that if it isn't the real problem...is it possible I just made bad gearing choices here? Maybe I just don't need a granny on this bike, and should just live with the bigger chainrings and get larger cogs?
No, those gearing options are legit. They shouldn't skip. That said, you could probably go with larger cogs and larger chainrings, preserving your gear ratios, and have a drivetrain that will be less susceptible to these effects. Say, a 14-27 rear and standard 30/42/52 road triple. But as it is, your gearing is similar to my MTB (except less range in the rear). It should work.

I hate to say it, but I'd probably get a new chain and new cassette, just for peace of mind so you know for sure there's no issues. Just make sure to get the chain length right, and check that B-screw.
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