Bicycle Mechanics - Rear Derailleur Question

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Valerian
07-31-10, 02:18 PM
Hello,

I am new and I was wondering if anyone can tell me why the cage of my rear derailleur is longer than the others. They said it is a 'long cage'. But why is it long and others in the group have a shorter one.

My rear is a Shimano 105 9-speed and the front used to be a triple 52/42/30 but I changed it to a double 53/39 months ago.

Do I need to buy a short cage? It seems to work fine as is.

Al1943
07-31-10, 02:30 PM
It is long because triple cranksets need long rear derailleurs to take up the chain slack when using the 30t chainring (granny gear). Long cage derailleurs have more "chain wrap" capacity.
With your current gearing you could use a shorter cage derailleur but there is nothing wrong with using the long cage derailleur other than a slight weight penalty.
Valerian
07-31-10, 02:33 PM
It is long because triple cranksets need long rear derailleurs to take up the chain slack when using the 30t chainring (granny gear). Long cage derailleurs have more "chain wrap" capacity.
With your current gearing you could use a shorter cage derailleur but there is nothing wrong with using the long cage derailleur other than a slight weight penalty.

i see, thanks. i guess i don't need to change it and saved me some money. it is also shifting fine and i don't want to mess it up.