The Definitive Guide to Mullet Drivetrains

The "Mullet" drivetrain has become the gold standard for gravel racing and bikepacking. By pairing drop-bar shifters (Road) with a massive wide-range cassette (MTB), you get the speed for the flats and the winching gears for the steepest climbs.

The Problem: Cable Pull & Protocols

You can't just bolt a Shimano XT derailleur to your 105 shifters. Road and MTB components typically use different "languages":

• Mechanical: Different cable pull ratios (how much cable moves per click).
• Electronic: Different wireless protocols or firmware blocks.

Solution A: The SRAM AXS Ecosystem (Easiest)

SRAM made this easy. All AXS components talk to each other. You can pair SRAM Red/Force/Rival AXS shifters with an Eagle AXS (XX1/X01/GX) rear derailleur.

Solution B: The Shimano GRX/Di2 Mix

Shimano is stricter. Officially, GRX is the widest range you can get (11-42t or 10-51t on 12s). However, for 11-speed Di2 users, you can often run an XT Di2 rear derailleur if you use the correct junction box setup, though it is not officially supported in the E-Tube app for all combinations.

Solution C: Mechanical Hacks (Tanpan / Shiftmate)

For mechanical purists, you need a "translator." Devices like the Wolf Tooth Tanpan change the cable pull ratio, allowing a road shifter to pull the correct amount of cable for an MTB derailleur.