Shifting Advice Needed
Last Post 06/06/2013 05:10 PM by Arnold Glim. 9 Replies.
Author Messages
Mr.Earl

Posts:6

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06/05/2013 07:49 PM
Need some advice. I recently purchased a Centaur 10-speed 12/30 cassette for my medium cage Campy Record derailleur. It has a Campy Record chain with a .25 measured stretch. It was working great with my Record 13/29 cassette. Anyway, I’ve gotten it to shift perfectly on the bike stand, but on the road it sometimes jumps or rides on the 2nd and 3rd largest cogs (the last 3 large cogs come as an integrated unit). I’m not certain which way the chain is moving as I usually have to slam it into the lowest gear. Any suggestions?
jmdirt

Posts:755

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06/05/2013 08:59 PM
Loosen the cable adjuster two "clicks", if it makes it worse, tighten it four.
Mr.Earl

Posts:6

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06/05/2013 09:16 PM
My adjuster doesn't click. Do you mean 1/4 turns, 1/2 turns? I did quite a bit of tension adjusting to get it to work on the bike stand, and sometimes it works nicely on the road. I run into problems while shifting into low gear on steep hills.
Oldfart

Posts:490

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06/05/2013 10:51 PM
Might be that the chain is worn too much for the new cassette. A
Mr.Earl

Posts:6

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06/05/2013 11:22 PM
That was my thought too, but my Park chain stretch measuring tool doesn't show very much wear. Campy Record chains cost a lot, and I would hate to change it only to get the same results. I suppose I'll have to try changing it, unless someone has a different suggestion. Do you think going from 13/29 to 12/30 is affecting the shifting. It doesn't seem like that's big a difference.
jmdirt

Posts:755

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06/05/2013 11:31 PM
There are no detents on the adjuster barrel? I'm with oldfart, if you are having trouble under higher loads, its probably the chain and cassette not liking each other. Does the top pulley wheel clear the 30 cog?
79pmooney

Posts:1192

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06/06/2013 01:29 AM
Are you saying the chain has stretched 1/4" in 12" (6 pairs of links)? That is huge! 1/16" is real. 1/8th" and both the cassette and chain are toast. 1/4"? I'm surprised any of the cassette even sorta works. I would get that chain within 100 yards of any cog or chainrings you care about.

On rereading your post, I gather you are at 1/4 of the allowable stretch as per the Park measuring device. I've never used a measuring tool, just a tape measure. Try doing it with a tape measure, measuring the front (or back) edges of pins 6 pairs of links apart and come back and tell us what you get. It will be a hair over 12". (Keep the chain tight. You don't have to pull hard, but you do have to pull out all the play.)

You may have to change the chain, but all is not lost. Hang on to that chain. With time, your new chain will be the same length. Now you have two chains. Swap back and forth and get twice the mileage out of both the chains and the cassette.

Ben
velofellow 2.0

Posts:27

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06/06/2013 04:40 PM
If you can live with yourself, you can buy a Campy compatible KMC chain for a lot less moola, and see if that makes a diference.
Keith Richards

Posts:759

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06/06/2013 04:55 PM
I have purchased TWO Campag chains over the 18 years I have had Campag on my bike. The others have always been aftermarket.
----- It is his word versus ours. We like our word. We like where we stand and we like our credibility."--Lance Armstrong.
Mr.Earl

Posts:6

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06/06/2013 05:10 PM
Actually, I have an unused Campy chain as I bought two when they were on sale, but I think my chain is still good. .25 of allowable stretch is practically new. Anyway, I tightened the cable tension on the stand while the chain was in low gear, and it seems to stay on the cogs well. I'll have to take it out on the road and head up hill, and see what happens. In any case, I'm more concerned about how it shifts in the low gears. I can live with some sloppy shifting on the high end, as I'm getting too old to push those high gears anyway.


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