In terms of popularity, both here on the staff and our customers, SRAM is the rear derailleur of choice. Functionally the same as the X.O, the SRAM X-9 Rear Derailleur uses more aluminum and features serviceable pulleys. In terms of durability, this one should stand up to more use and abuse. As with all SRAM 1:1 derailleurs you can choose trigger or twist and both will work great.

The SRAM X-9 rear derailleur is available in three cage lengths -- short, medium and long. There is a good reason for the different lengths, and we explain in our description of the SRAM X.O rear derailleur. For those who think they understand, we'll leave you with the equation: TDC (Total Derailleur Capacity) = (biggest cog minus smallest cog) + (biggest chainring minus smallest chainring)

Total capacity is 37t for the Medium cage, and 45t for the Long. The derailleur works with both eight and nine speed cogs and shifters and is compatible with all 1:1 shifters.