mattzees

I just popped a spoke on my rear wheel. I was going pretty quick, the spoke got caught in my chain, and wrecked my rear derailleur. It's completely bent up, missing a gear, etc.

I have a full Shimano Ultegra group, double in front, 9-speed in the rear. I need to buy a replacement derailleur, and I see a bunch on EBay, but I have some questions first:

1) Some of the derailleurs I see listed are described as "triples". I thought all 9-speed Ultegra rear derailleurs were the same. Does it matter if my front gear is a double or a triple? Why would this affect which model or rear derailleur I buy?

2) What is the difference between long-cage and short-cage derailleur? How do I tell which one I currently have? Does one perform better than the other?

3) Is there a model numer on my derailleur somewhere that I'm just not seeing? A model number would make things a lot simpler.

Thanks.

KevinF

A "triple-compatible" rear derailleur is the long-cage version. Due to the small size of the granny gear on a triple, the derailleur has to be able to take up a lot of chain slack; therefore, the long-cage version is (usually) needed for triple setups.

Long cage derailleurs shift a tiny bit slower then their short-cage counterpart, but both will work just fine with double-cranksets.

Long cage picture here.

Short cage picture https://bike.shimano.com/catalog/cycl...=1151452708914.

Those pages also contain the model numbers, although I don't know if they're easily visible (I don't have an Ultegra derailleur in front of me). You should be able to determine which you have from the pictures as the long-cage version is pretty long.

capwater

Ultegra rear derailleur model number RD-6500.