Rear Derailleur Size

The Kalmyk

Well-Known Member
I'm looking at rear derailleur's for my new bike and saw there are different cage sizes:confused:...How do small/med/large cages differ in performance and function...Of course a 29er bike we are talking here and I'm thinking that might eliminate the short cage....For all the SSpeeders out there fire away:D
 

stb222

Love Drunk
Jerk Squad
The different cages limit the max cogs size in the largest gear combination and shorter cages have better clearance and supposedly shift better due to less flex between the pulleys. If you are using that bike up north, you could probably get away with a 2X9 setup, in which case you can use a med cage derail. You just have to look at the max tooth size recommended by the manufacturer.

Which S you going with? I highly recommend shimano's shadow dérailleurs, especially on a bike your are planning to ride in the rocks. The way it tucks underneath the cassette is nice.
 

BiknBen

Well-Known Member
Wikipedia said:
Cage length
The distance between the upper and lower jockey wheels of a rear derailleur is known as the cage length. Cage length defines the capacity of a derailleur to take up chain slack. What cage length is needed for a particular drivetrain setup depends on the sum of two numbers: the size difference between the largest and smallest rings on the crankset, and the size difference between the largest and smallest sprockets on the cassette/freewheel. A larger sum requires a longer cage length. Typical cross country mountain bikes with three front chainrings will use a long cage rear derailleur.

The cage needs to be long enough to take up the slack of the chain when you are in the smallest chainring and smallest cog combo.
 

hardtale70

She's Gone From Suck to Blow
Shop Keep
I'm 2x9 w/ a 24/32 up front and the xt cassette w/ the 34 tooth in the back. Ive rocked a short cage xt forever, it's flawless..............
 

The Kalmyk

Well-Known Member
Running a smaller cage means you have to run a shorter chain, right:confused:.How will a shorter chain affect the feel of the drivetrain? Am I being to anal about this?
 

jimvreeland

Endurance Guy: Tolerates most of us.
You can run the Mid-cage with a full 3x9 setup, even with a 11-34t cassette, even on a 29er and not have a single issue. I run a short cage with my 1x9 and 2x9 setups , again with no issues (with the derailleur at least). Also all Shimano MTB derailleurs are designed to work with a 34T cog so you'll have no clearance issues with the upper pulley. I 2nd the "shadow" option. I'd like to add that cage length doesn't change it's shifting characteristics/precision and none of them are stiffer than another. There is a slight, but very negligible, increase in chain tension on the short cage.

-Jim.
 

Fogerson

Former Resident Nerd
Haha!

I was so anal about clean crisp shifts, and thusly rings/chain/derailleur, I chucked 'em all and went SS.

Always shifts quickly and quietly :)
 

The Kalmyk

Well-Known Member
Haha!

I was so anal about clean crisp shifts, and thusly rings/chain/derailleur, I chucked 'em all and went SS.

Always shifts quickly and quietly :)

I come from the flip side of that...SS first then geared:D...It will always be in that order
 

The Kalmyk

Well-Known Member
helphelphelp

stb222 posted up pics of his Shimano Shadow der...I used the search option without luck...Can someone please help me find this thread:eek::eek:
 
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