# Medium cage vs. short cage



## red elvis

why do some people prefer a short cage over medium cage rear derailleur? will a short cage RD works on a 11-28t cassette? :idea:


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## Blue CheeseHead

Medium/long cage derailleurs are needed for triples or large rear cassettes (usually larger than 28t). There is a slight weight penalty for the medium/long cage, but I have not noticed a difference in performance on a typical setup. If you think you might want to run big cogs for hill climbs, there is no reason not to just switch to a medium or long cage and ride it all the time. (except looks  )


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## AdamM

Faster shifts. I know I've gotten the 27t Shimano to work just fine with a short cage, so my hunch is that the 28t SRAM would be ok too.


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## red elvis

I knew it. I should've ordered a short caged instead of a medium caged 105 RD. I just realize that I had a triple fsa before i switched to a 105 compact crank. that's the reason why i had a medium caged tiagra. Thanks for the replies, guys.


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## redondoaveb

AdamM said:


> Faster shifts. I know I've gotten the 27t Shimano to work just fine with a short cage, so my hunch is that the 28t SRAM would be ok too.


Short cage works fine with 28t sram.


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## Kontact

AdamM said:


> Faster shifts.


Huh?


The only difference between the two is the amount of chain slack they can take up.


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## chas0039

Kontact said:


> Huh?
> 
> 
> The only difference between the two is the amount of chain slack they can take up.


In theory, the fact that the short RDs have a shorter cage means that the amount of movement is less due to the lower angle and lower flex. I can't personally comment on that, but other say it has been measured and the shift time is quicker.


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## Kontact

chas0039 said:


> In theory, the fact that the short RDs have a shorter cage means that the amount of movement is less due to the lower angle and lower flex. I can't personally comment on that, but other say it has been measured and the shift time is quicker.


Movement of what? Flex where? Measured by whom?


Long cage derailleurs "move" less per shift, because a few degrees of pulley arc takes up more chain slack than a short cage derailleur.


The only positive thing I'd say about short cage derailleurs are that they are lighter, and sometimes offer more spring tension on the chain due to the shorter lever arm. Otherwise, the two operate identically, placing the upper (shifting) pulley in exactly the same way. So I really don't follow what you are talking about.


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## PlatyPius

Medium cage/long cage look "Fredly". That's most likely the #1 factor leading to the use of short cage even when a medium would be better.


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## Drew Eckhardt

PlatyPius said:


> Medium cage/long cage look "Fredly". That's most likely the #1 factor leading to the use of short cage even when a medium would be better.


Pie plate sized rear cogs like a 28 or worse look bad too.


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## cxwrench

AdamM said:


> Faster shifts. I know I've gotten the 27t Shimano to work just fine with a short cage, so my hunch is that the 28t SRAM would be ok too.


you've fallen victim to the old myth that shorter cage derailleurs shift quicker. the shift takes place at the upper pulley...cage length has nothing to do w/ shift speed as other posters have stated. it just wraps more chain...that is all.


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## chas0039

Don't shoot the messenger guys. I have no dog in this fight. I'm just reporting what I have read and seen documented concerning the reasons people prefer short over longer shifters. I you think differently, no skin off my knees. I don't care one way or the other. I use short where it is called for and longer when short isn't enough.


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## Kontact

chas0039 said:


> Don't shoot the messenger guys. I have no dog in this fight. I'm just reporting what I have read and seen documented concerning the reasons people prefer short over longer shifters. I you think differently, no skin off my knees. I don't care one way or the other. I use short where it is called for and longer when short isn't enough.


No one is shooting the messenger. You've just made some interesting claims that you say are backed up by data:

Tell us more.


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