what is the difference between sram x.9 short cage and long cage?

Question

im just looking at buying an sram x.9 and wanting to know why there are the short cage, medium cage and the long cage.

Answer 1

Actually - the descriptions above are right...

But you need to know this too: It has to do with what's called "chain wrap" more than anything else. This is the sum of the differences between the gearing.

For example on my bike I run an 11~34 cassette and 36~24 chain rings. 34 - 11 = 23 and 36 - 24 = 12... 23 + 12 = 35... I run a X.0 black box medium cage on my Remedy 66.

http://www.sram.com/_media/pdf/sram/dealers/TM_RoadMTB_MY07_E.pdf

If you scroll to the page for the X.9 you'll see it illustrated there as "Total" This is what matters, especially with Sram because it has no sprung B-knucle. It is easy to snap the derraileur off if this measurement comes up short!

Also- the secret to Sram's rock solid shifting is no spring in the B-Knucle, no cable loop, and no floating jockey pulley.

Long story short, when you blast through the rock garden, you come out of it in the gear you started it in.

I've been racing on this stuff since it was Sachs Plasma back in 1999! It rocks, I run X.0 now!

Answer 2

put simply, it's the length of the cage.

The cage is the part that hangs below the derailleur, that has the two little pulley wheels - known as 'jockey wheels' - that the chain crisscrosses through. The length of the cage is determined by the distance between the axles of the jockey wheels.

A long cage is used when there is a large difference between the gear ratios, typical of a mountain bike.
A short cage is used when the difference in ratios is small, like on a road racing bike.
A medium cage would be used on a 'racing triple' or a hybrid where there are three chainrings in fron that are somewhat close in size and a smaller cassette.

The longer cage is necessary to take up the extra slack when using a small chainring and smaller cog, but still allow the chain to be long enough for a large chainring/larger cog combination.

The shorter cage weighs less and doesn't need to take up extra chain slack so the chain can be shorter and therefore lighter. You won't find a short cage on anything but a bike set up for racing, or 'race ready'.

Answer 3

Sram X9 Short Cage

Answer 4

What madmonkey said, but some downhill bikes and freeride use the med or short cage, so the chain won't rattle as much and they don't have that high number of tooth in the cassette.