SRAM X01 DH Rear Derailleur - 7-Speed Short Cage Black with Clutch A3 Model-Forerunner 255 If you have a round

If you have a round seat tube with no braze-on mount

}KMC Reversible Chain Tool

Free Chain in bottom cog (unsupported chain - shorter is better and will increase shifting precision):

Color Black Rail Material Titanium Primary Color Black Gender Unisex Saddle Dimensions 145 x 245mm

Application: Trail/Cross Country

SRAM X01 DH Rear Derailleur - 7-Speed Short Cage Black with Clutch A3 Model-Forerunner 255 If you have a roundSRAM X01 DH Rear Derailleur 7 Speed Short Cage Black with Clutch A3. The 7 speed X01 DH rear derailleur makes shifting smooth and reliable no matter where you ride. Engineered to maintain consistent chain gap across all seven gears it eliminates vertical movement for faster shifting reduced shift force and an end to ghost shifting. The clutch features a smoother torque curve for a quieter more consistent operation and feel. The 12 tooth X SYNC pulley