SRAM's Red XPLR AXS E1 is the flagship rear derailleur in the new 13-speed gravel lineup, and it borrows heavily from the T-Type mountain bike playbook. The Full Mount design eliminates the derailleur hanger entirely to improve shifting and increase durability, bolting directly to the frame around the rear axle. If your gravel frame has a UDH-compatible dropout and you're building a 1x13 drivetrain, this is the derailleur at the top of the hierarchy.

The Full Mount interface is the headline change, and it matters for two reasons. Shifting precision improves because the derailleur is referenced to the axle rather than a bolt-on hanger that can flex or get bent, and impact resistance goes up because there's no sacrificial hanger to snap when something catches the cage. The derailleur only works on frames that accept UDH derailleurs, and it's a 1x-only design — there's no front derailleur option in the XPLR ecosystem.

Compatibility is narrower than a traditional derailleur, so it's worth being explicit. It pairs with SRAM's XPLR 13-speed cassettes, runs SRAM Flattop chains, and is not compatible with SRAM T-Type chains. Cassette range tops out at 46T, which is the ceiling for the current 10-46T XPLR cassettes across Red, Force, and Rival E1 tiers. If you need more low-end range than that, the mullet route with an Eagle AXS mountain derailleur and MTB cassette is still on the table — but that's a different build, not this derailleur.... Read More