If you’ve ever tried to purchase a derailleur, one question that might come up…”what size cage?”
Here’s a brief explanation that you could refer to:
Short Cage: Used for cassettes with 11-30T
Medium Cage: Used for cassettes with 11-32T
Long Cage: Used for cassettes with 11-34T
In the event you didn’t know what the “T” stood for, that means teeth. For example the 11 would be your smallest gear and the 34 would be your biggest gear in the back.
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I have heard through the years that mid-cages work better when using a 34T cog than a long cage, has any one tried it?
That’s not really accurate. The number of chainrings plays a bigger impact.
Every derailleur has a rated capacity (ability to take up chain slack) measured in teeth. To calculate capacity, take (big chainring – small chainring) + (biggest cog – smallest cog).
For example – a Shimano long cage RD has a rated capacity of 45T, while their medium cage is rated at 33T.
If you have a standard MTB config (22/32/44 crank, 11-34 cassette), you’d need a capacity of at least (44-22)+(34-11) = 45T. You should go with the long cage in this case.
If you ran just two chainrings (32/22), you’d need a capacity of at least (32-22)+(34-11) = 33T – in which case a medium cage will work.
What Weyland says is accurate.
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Weyland hit the nail exactly on the head, this is the correct cassette to cage math. Super simplified too!
If I decide to go 2 X 9 on my current build, mosdef going for a mid cage for a 11-34 with 32-22.
Kool, soi can use a medium cage on SLX compact drive train, sweet!