Bicycle Mechanics - 13-26 cog, what length rear D to use?

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grinderbob
07-16-06, 07:48 AM
should I use short or long cage? thanks.


tgomes
07-16-06, 07:56 AM
I have used a Dura Ace and an Ultegra with a 12-27 with no need of a long cage. I believe shimano gives 26 or 27 as a max cog.

Wil Davis
07-16-06, 08:14 AM
should I use short or long cage? thanks.

Either should work, but a short cage will give a snappier shift. The long cage RD is used on a set up with a triple chain ring.

- Wil


bccycleguy
07-16-06, 09:48 AM
I have used a SG long cage Ultegra RD on a 12-28 with a triple crank (52-39-30) set up and it worked well.

Why not get the derailleur capacity on the manufacturer's web site (i.e. Shimano) and do your own calculation. Info on Shelden Brown's web site about capacity.

'nother
07-16-06, 11:13 AM
Either should work...The long cage RD is used on a set up with a triple chain ring.
+1 FTW. Cage length corresponds to difference of the largest-smallest chanrings, not rear cog size. Any standard "road" RD should work with 13-26. Larger than 30 or so and you might need a "mountain" RD (which has a larger parallelogram, and that is the key factor for cog size...only coincidentally has longer cage length 'cause they usually are mounted on bikes with triples up front). As suggested, have a look at the specs for different cage lengths . . . rear cog capacity is exactly the same for all of them, short, medium, and long; only thing that changes is the "front difference" metric.



, but a short cage will give a snappier shift.
I'm not sure I really buy that bit. There may be a few milliseconds difference but I'm very skeptical that it's any significant difference in "snappiness" outside of one's mind.

John E
07-16-06, 05:39 PM
If you really want both the short cage and the 26T inner cog, consider a slightly smaller outer chainring, such as a 50 or even a 48, instead of the default 53.

Big R
07-17-06, 11:48 AM
Easy...if you're using a double...short cage is the preffered set-up.
With a triple you'll want a long cage.