The SRAM GX 1x11 is a long cage rear derailleur for 11 speed 1x drivetrains with cassettes up to 42t. X-HORIZON geometry and a clutch keep the chain quiet and shifts consistent.

What it's for

A replacement or upgrade derailleur for SRAM 1x11 mountain bike drivetrains.

How it works

X-HORIZON: a straight parallelogram keeps the derailleur moving only side to side. That prevents ghost shifting and lowers shift force, and the large upper pulley offset keeps the chain gap constant.

Roller Bearing Clutch: controls the cage so the derailleur does not bounce and the chain does not slap.

Cage Lock: push the cage forward and lock it to make chain slack for wheel removal and chain installation.

X-Actuation: SRAM's cable pull ratio for 1x drivetrains. It keeps shifts consistent across the whole cassette.

12t X-SYNC pulleys run on sealed cartridge bearings.

Compatibility

• Cassette: 11 speed, up to 42t
• Shifter: SRAM 11 speed X-Actuation
• Chain: SRAM 11 speed
• Drivetrain: 1x
• Does not fit: 12 speed Eagle drivetrains

Specs

• Speeds: 11
• Cage: long, aluminum
• Max cog: 42t
• Pulleys: 12t X-SYNC, steel bearings
• Weight: 265 g
• Model: RD-GX-1-A1
• Part number: RD6129

Pairs with

• SRAM GX XG-1150 Cassette
• SRAM PC-1130 Chain