Gravel derailleurs and derailleur hangers

What sets a gravel derailleur apart?

A gravel derailleur works like a road derailleur, but it is designed for the impacts and vibrations of tracks. Its longer cage takes up the difference in teeth of a very wide-range cassette. A stabiliser, often called a clutch, slows the forward movement of the cage: the chain slaps less against the chainstay and is less likely to drop off the chainring on a bumpy track. Shimano calls it Shadow RD+ on its GRX derailleurs; for its XPLR AXS derailleurs, Sram chose a liquid silicone damper called Orbit.

Gravel rear derailleur: 1x or 2x, what capacity?

Two values count in the specifications: the maximum size of the largest sprocket and the capacity, the sum of the difference in teeth between the smallest and largest sprockets and the difference between the chainrings. A derailleur designed for a double chainring keeps a shorter cage; a 1x derailleur accepts a much larger sprocket, but no second chainring.

• Shimano GRX Di2 11-speed: the RD-RX815 is fitted in 2x with a cassette up to 34 teeth, while the RD-RX817 is reserved for single-chainring set-ups.
• Shimano GRX 12-speed: the RD-RX820 accepts a 36-tooth sprocket in 2x, and the long-cage RD-RX822 goes up to 51 teeth in 1x.
• Sram XPLR: the 1x derailleurs from the Apex, Rival, Force and Red groupsets are designed for XPLR cassettes up to 44 teeth.

A derailleur only works with the shifters of its own system: same brand, same number of speeds and same technology, mechanical with a cable, electronic Di2 at Shimano or wireless at Sram and Campagnolo.

Gravel front derailleur for a double chainring

On a 2x gravel bike, the front derailleur follows a chainset whose chainline is moved outwards to leave room for wide tyres. Shimano's GRX FD-RX810 therefore only works with GRX chainsets, and Sram's Rival eTap AXS Wide is designed for Wide chainsets in 43/30, with tyres up to 45 mm. Also check the mount: braze-on, on a tab welded to the frame, or clamp-on, around the seat tube, whose diameter you will need to measure.

Which derailleur hanger do I need?

An intermediate part between the frame and the rear derailleur, the hanger is designed to give way first: in a crash or an impact, it is the hanger that bends or breaks, and the frame is spared. For a long time each manufacturer designed its own hangers, hence hundreds of references: identify yours by the make, model and year of the bike, by the number engraved on the part, or by comparing its shape, its mounting holes and the type of axle, quick release or thru-axle.

To simplify matters, Sram launched the UDH, a universal derailleur hanger that many gravel and MTB frame manufacturers have adopted: it is available everywhere and pivots backwards on impact. It also makes it possible to fit Sram T-Type derailleurs, mounted directly on the frame without a hanger. When touring, a spare hanger at the bottom of your bag saves you from being stranded far from anywhere.

Road and MTB derailleurs and drivetrain parts

Gravel bikes share many parts with road and mountain bikes: depending on your groupset, road derailleurs or MTB derailleurs offer other references, and city bikes find theirs among our city bike derailleurs. A new derailleur is easier to adjust with a chain and a cassette in good condition; to change everything, see our gravel groupsets or the whole gravel drivetrain range.

Which brands for gravel derailleurs and hangers?

Marwi specialises in derailleur hangers: each reference in its GH series is linked to the frame brands it fits, from Focus to Bergamont, Stevens or Orbea, which speeds up the search.

Shimano dedicates its GRX range to gravel, with rear derailleurs featuring the Shadow RD+ stabiliser, such as the RD-RX817 Di2 for single-chainring set-ups, and the FD-RX810 front derailleur matched to the chainline of GRX chainsets.

Sram offers its XPLR derailleurs for single-chainring gravel bikes, from the mechanical Apex XPLR to the long-cage wireless Rival, Force and Red eTap AXS versions, as well as Wide front derailleurs for widened double chainsets.

Look, the frame maker from Nevers, supplies the original hangers for its models, such as the 765 Disc or the 795, with their bolts.

Campagnolo offers its wireless Super Record WRL, including a 13-speed version compatible with the UDH hanger, as well as Chorus and Record derailleurs and a UDH hanger under its own name.

Bombtrack, a Cologne brand focused on touring and adventure, supplies the hangers for its own frames, including a version to the Sram UDH standard.

Gravel derailleurs on sale

End-of-line derailleurs and hangers are offered in our road clearance, and new references arrive in new arrivals. Black Friday and the seasonal sales are good times to upgrade a drivetrain.

Frequently asked questions

How do you know which derailleur hanger to buy?

Remove the old hanger and compare it with the photos and references: shape, number and position of the holes, type of axle. The number engraved on the part, or the make, model and year of the frame, will lead you to the compatible reference. If in doubt, the bike manufacturer or a workshop can confirm.

Do you need a specific derailleur for a gravel bike?

Not always: a road derailleur works on a gravel bike as long as it accepts the cassette fitted. Gravel derailleurs add a chain stabiliser and greater capacity, two real advantages on tracks and with a very wide-range cassette.

Can you fit an MTB derailleur on a gravel bike?

In some cases. At Sram, all AXS parts communicate with each other, which makes it possible to pair road levers with an Eagle AXS MTB derailleur. With mechanical groupsets, cable pull often differs between road levers and MTB derailleurs: check the compatibility stated by the manufacturer before you buy.

My derailleur shifts badly: should I replace it?

Not necessarily. First check the alignment of the hanger, often slightly bent after a crash, then the condition of the cable and outer housing and the tension adjustment. A derailleur needs replacing when its pivots have developed play or its cage is bent; worn jockey wheels can be changed separately.

Does the chain stabiliser make shifting stiffer?

It adds slight resistance to the movement of the cage, noticeable mainly with a mechanical shifter. On some models, a lever lets you switch it off, for example to remove the rear wheel more easily. On tracks, it is best left on.