What Is a Direct Mount Derailleur Hanger? Standard vs. Direct Mount + UDH

Trying to figure out whether you need a standard mount or Direct Mount derailleur hanger? The difference comes down to how the rear derailleur attaches to your bike.

A standard derailleur hanger works with the derailleur's standard mounting configuration. A Shimano Direct Mount hanger allows a compatible Shimano rear derailleur to attach directly to the hanger with the B-Link removed.

And if your bike uses the SRAM UDH frame standard, there is another option. Wheels Manufacturing now offers UDH-compatible Direct Mount hangers that allow compatible Shimano road, gravel, and mountain derailleurs to mount directly to UDH-compatible frames.

What Is a Standard Mount Derailleur Hanger?

Most replaceable derailleur hangers use an M10x1 threaded mounting hole where the rear derailleur attaches.

The location of that hole matters. Rear derailleur manufacturers design their shifting systems around a specific relationship between the derailleur, cassette, rear axle, and wheel.

Key features of a standard replaceable derailleur hanger.

On a standard hanger, a compatible Shimano Direct Mount derailleur uses its B-Link between the derailleur body and the hanger.

Frame → Standard Hanger → B-Link → Rear Derailleur

Standard mount hangers remain widely used and work with a broad range of rear derailleurs.

What Is a Shimano Direct Mount Derailleur Hanger?

Shimano introduced its Direct Mount system to move the derailleur's upper pivot farther back and create more room around the rear dropout.

Instead of attaching the derailleur through the B-Link, a compatible Shimano rear derailleur attaches directly to a Direct Mount hanger with the B-Link removed.

Frame → Direct Mount Hanger → Rear Derailleur

Standard Mount Derailleur

Direct Mount Derailleur Direct Mount hanger, no B-Link

Direct Mount Derailleur Standard hanger with B-Link

Removing the B-Link creates a cleaner connection between the hanger and derailleur and provides more room around the rear axle and dropout.

For bikes and derailleurs that support it, Direct Mount can also make rear wheel removal and installation easier.

Standard Mount vs. Direct Mount: What's the Difference?

The biggest difference is the location of the derailleur mounting point.

A standard hanger positions the derailleur correctly when the Shimano B-Link is installed.

A Direct Mount hanger moves that mounting point so a compatible Shimano derailleur can attach in the correct position without the B-Link.

That's why two derailleur hangers can fit exactly the same frame but still not be interchangeable from a derailleur compatibility standpoint.

The hanger needs to match both your frame and your derailleur configuration.

Standard Mount DROPOUT-266

Shimano Direct Mount DROPOUT-350

Same frame interface, different derailleur position. Matching the hanger to both the frame and derailleur configuration matters.

Can a Shimano Direct Mount Derailleur Work With a Standard Hanger?

Yes. Many compatible Shimano Direct Mount derailleurs can be installed in either configuration.

• Standard Mount Hanger: Use the derailleur with its B-Link installed.
• Direct Mount Hanger: Remove the B-Link and attach the derailleur directly to the hanger.

This flexibility is one of the advantages of Shimano's Direct Mount design.

Can a Standard Mount Derailleur Work With a Direct Mount Hanger?

No. A traditional standard-mount derailleur requires the mounting position provided by a standard derailleur hanger.

Because a Direct Mount hanger places the derailleur mounting hole in a different location, it should only be used with a compatible Direct Mount derailleur configured correctly for that hanger.

What About UDH Frames?

This is one of the biggest changes since we originally published this article.

SRAM's Universal Derailleur Hanger, or UDH, created a standardized hanger-to-frame interface that is now used by a wide range of bike manufacturers.

Wheels Manufacturing now offers Direct Mount hangers designed around the UDH frame interface.

These hangers replace the standard UDH and allow compatible Shimano derailleurs to use a Direct Mount configuration on a UDH-compatible frame.

Shimano Direct Mount for UDH Road and Gravel Bikes

DROPOUT-562 The Wheels Manufacturing DROPOUT-562 adds Shimano Direct Mount compatibility to UDH-compatible road and gravel frames. It is optimized for compatible models from: Shimano Dura-Ace Shimano Ultegra Shimano 105 Shimano GRX The derailleur installs without the B-Link. DROPOUT-562 is CNC machined from 6061 aluminum in our Colorado shop, uses an M12x1.0 thru-axle thread pitch, and retains the ability of the original UDH design to rotate under an impact to help protect the derailleur. SHOP DROPOUT-562

Shimano Direct Mount for UDH Mountain Bikes

DROPOUT-653 The Wheels Manufacturing DROPOUT-653 adds Shimano Direct Mount compatibility to UDH-compatible mountain bike frames. It is optimized for compatible Shimano models from: Saint Deore Deore XT SLX Altus Like DROPOUT-562, it is CNC machined from 6061 aluminum in Colorado, uses an M12x1.0 thru-axle thread, installs with the B-Link removed, and retains the rotational impact protection of the original UDH design. SHOP DROPOUT-653

Is Shimano Direct Mount the Same as SRAM UDH?

No. This is an important distinction.

UDH describes the interface between the frame and derailleur hanger.

Shimano Direct Mount describes how a compatible Shimano derailleur connects to the derailleur hanger.

A Wheels Manufacturing UDH Direct Mount hanger combines the two ideas: it fits the UDH frame interface while providing the mounting position required for a compatible Shimano Direct Mount derailleur.

Is Shimano Direct Mount the Same as SRAM Full Mount?

No.

Shimano Direct Mount still uses a replaceable derailleur hanger between the frame and derailleur.

SRAM Full Mount derailleurs use the UDH-compatible frame interface differently and mount around the rear axle interface without a conventional derailleur hanger.

The systems should not be confused simply because both create a more direct derailleur-to-frame connection.

Which Derailleur Hanger Setup Do I Need?

Standard Rear Derailleur

Use a standard mount derailleur hanger.

Shimano Direct Mount Derailleur + Standard Hanger

Keep the B-Link installed.

Shimano Direct Mount Derailleur + Direct Mount Hanger

Remove the B-Link and attach the derailleur directly to the hanger.

UDH Frame + Compatible Shimano Road or Gravel Derailleur

The DROPOUT-562 may allow you to convert your bike to Shimano Direct Mount.

UDH Frame + Compatible Shimano Mountain Derailleur

The DROPOUT-653 may allow you to convert your bike to Shimano Direct Mount.

SRAM Full Mount / Transmission Derailleur

The derailleur uses the UDH-compatible frame interface without a conventional derailleur hanger.

Why Does the Correct Derailleur Hanger Matter?

A derailleur hanger might be a small part, but its position plays a major role in how well your bike shifts.

The hanger determines where the rear derailleur sits in relation to the cassette. If the hanger is bent, damaged, poorly aligned, or simply the wrong model, getting consistent shifting can be difficult no matter how carefully the derailleur is adjusted.

That's why matching the correct hanger to the frame, model year, and derailleur configuration matters.

Wheels Manufacturing replacement derailleur hangers are CNC machined in our Colorado shop to exacting tolerances and are available for hundreds of bike models.

Find the Right Direct Mount Derailleur Hanger

Not sure which hanger you need? Start with your:

• Bike brand
• Bike model
• Model year
• Rear derailleur model
• Current hanger or UDH configuration

Still not sure? Contact Wheels Manufacturing with your bike brand, model, year, and rear derailleur model, and we can help confirm the correct hanger before you order.