# Tech Experts: SRAM GX 2x11 cage length???



## SVO (May 25, 2005)

2x11 GX RD comes in mid and long cage. SRAM doc says mid cage is for hardtail only. Does that mean it's better for hardtail? Why? Building a 2X rigid 29+ rig. Searched everywhere- thanks!
JD


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## dbhammercycle (Nov 15, 2011)

Long cage derailleurs can take up more slack in the chain so you can have a wider gear range. I would assume that all the movement in the rear triangle of a FS could require a longer cage derailleur? The mid cage will not hang as low, so maybe it will catch less crap or be less likely to get hung up on trail branches, weigh less and the chain will weigh less because you don't have as many links. As far as your build goes, go with what works based on your largest expected gear ratio. Honestly, I wouldn't use a mid cage unless I was going 1x, especially if you will have a big 42 in the rear cassette.

old thread, but may be helpful
http://forums.mtbr.com/drivetrain-s...ong-cage-vs-short-cage-derailleur-205890.html

The old wisdom (9 speed) states a 3x uses a long cage, 2x uses a mid cage. 10 speed isn't so cut and dry, it depends on the sizes of the biggest chain ring and the biggest cog in the cassette.

(big front-small front)-(big rear- small rear)=mech capacity or something like that


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## SVO (May 25, 2005)

Thanks.

Yeah, a long cage can wrap more and some FS designs change the stay length through travel so maybe that is it. Mid cage for sure is less likely to hit stuff (and the GX 2X is not the newer low profile design type) and probably more taught/less slap.

With 3x my old approach was to measure tooth difference between mid ring/small cog and large ring third cog in, as those are the tooth count extremes I use, and then make sure the RD can wrap up that much chain, go with the mid cage if it was enough, which it usually was.

But I believe modern 1X systems have the most need for wrap with 32 teeth (10-42 cassette), vs. say my example above, maybe (44+25) - (34+11) = 24. That assumes the rider is active/aware enough to not hit ugly cross-shifting of course. I certainly try to avoid cross shifting with 200lb me plus gear.

But both cage lengths have the same specs: Wrap: 46, Max Cog: 42. Strange. In any case it looks like I'd be well within spec using either, just wondering if there is some bikepacking consideration I should make- maybe mid cage to hit less brush/rock is it.


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## 6thElement (Jul 17, 2006)

Funnily enough I was trying to find the chain capacity specs on those two variations of the GX 2x11 yesterday and could only see 46T mentioned for both and the SRAM matrix that says medium only for HT. A full suspension will need more capacity from the long due to chainstay lengthening with suspension compression.

As I'm considering it as an update to the 3x9 on my rigid 29er I've got the medium length in my basket. Still trying to decide if I truly *want* this gearing change as it's definitely not a needed upgrade.


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