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Discussion Starter · #1 ·
Bought the bike used and I can't tell whether I have the short or medium RD...thinking about putting on a 13-29 to make steep hills a bit easier...
 

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do you use a double or a triple?

if double, short cage is probably what is on your bike

If you have a triple, its probably a medium.

If you can fit your finger inbetween the pullies, then its a medium cage. or in other words, If the teeth of the pullies like 1cm apart (or just big enough for a chian to fit through), then its a short cage.


either way, you should be able to use the 13-29 cassette.
 

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Discussion Starter · #3 ·
It's a double Campy 10. AFAIK, I don't think I'd need a 13-29 if I had a triple :)

The teeth between the pullies looks like around 2cm w/o chain or around 1cm w/ chain, so that probably means a short cage :-(


I thought I had to switch to a medium cage to avoid cross-chaining issues w/ the 13-29 (I'm worried about oopsing when I'm too tired to think straight and have the chain rip up the derailleur :)

Also planning on trying the Miche 13-29 campy 10 cassette to see if how well the setup works before getting a real campy 10 cassette.

BTW, is a long cage something that shouldn't be put on a campy 10 double? I was reading that it's only used on a triple and shifts aren't as crisp because there's less chain tension with a long cage...
 

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not true...

A longer cage won't adversely affect the shifting.

I would buy a Campy Veloce or Centaur cassette rather than an offbrand. Nashbar used to have them pretty cheap.

The facts regarding the use of a short cage with a 13-29 are as follows. If you increase the chain length by one inch (requires a new chain), you should not have a problem if you shift into the 53/29. With insufficient cage length, the chain will then hang loose in the little ring and one or two of the smallest cogs, making them unusable. A medium cage or long cage RD will make all the combination useable.

Using a short cage RD with the 13-29 will exceed the wrap capacity, so it's a nonstandard setup. Using the normal little ring/little cog setup would suggest a chain length that's 1 inch too short. Here's how to adjust the chain length properly.

Two simple tests will determine if the chain is the correct length. First, it must not hang loose in the little ring, little cog combination. If there is no tension on the chain in the little ring, little cog combination; remove two links (one inch) at a time, until there is. When the ends of the chain are brought together, some movement of the lower pulley should occur, indicating tension is being applied. Two more links (another inch) may need to be removed, beyond the point of absolute minimum tension, to keep the chain from rubbing on itself or the chain guide tab as it passes under the upper derailleur pulley. If you want to see how much lower pulley movement will occur, without removing the extra inch of chain, shift up four teeth (11 to 15 or 12 to 16). This has the same effect as removing two links. Once this is done, the chain is set to the maximum useable length. Removing additional links will do nothing but reduce the derailleur's capacity.

Second, the chain must be long enough to avoid over-extending the rear derailleur when shifted to the big ring and biggest cog combination. If the chain is set to the maximum length as described, it should always pass this test, unless your setup exceeds the derailleur's stated wrap capacity. If you deliberately exceed the derailleur's capacity and the derailleur is over-extended in the big ring/largest cog combo, then you must either avoid that combo or add another inch and avoid using the little chainring and the smallest 3 or 4 cogs (since the chain will hang loose).
 

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Discussion Starter · #5 ·
Thanks, C-40.
So if I understand your description correctly, you can adjust a short cage 13-29 setup so you either lose the big-big or the little-little combo depending on how you adjust the chain length (very probable) unless your setup happens to let those work depending on how things were installed (less probable)?

Looks like Nashbar no longer carries 13-29 cassettes, but carries Veloce (only in 12-25) for $75. The Miche 13-29 is only $48 at aebike...
 

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pretty much...

Chainstay length has some effect on the exact results when trying to get every last tooth of wrap, so what works on one bike won't be exactly the same on another. Using the shorter chain length is dangerous. You don't want to damage an expensive RD.

Here's the cheapest I could find the Veloce cassette, IMO it's worth the extra money.

http://www.glorycycles.com/cave10sp20ca.html

There is an even cheaper source, but it's in europe. Higher shipping charges and possible duties could cancel out a lot of the savings. It's a good place for a large order, though.

http://www.11speed.com/catalogo/dettagli_prodotto.asp?prod_id=105
 

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Visual cues

rufus said:
maybe this will help

Taking a cue from the visual appearance, here's how I remember:

Short cage: Lower pulley bolt lines up just inside barrel adjuster

Medium cage: Lower pulley bolt lines up just outside barrel adjuster

Long cage: Entire lower pulley lines up outside barrel adjuster
 
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