Bike derailleur hanger: definition, types, how to choose and adjust

What is a bike derailleur hanger?

A bike derailleur hanger is a small, replaceable metal or alloy component that connects the rear derailleur to the bike frame, positioned at the rear dropout to ensure precise alignment for accurate shifting. It was developed in the late 20th century as a sacrificial part to protect more expensive frame and drivetrain components in the event of crashes or impacts, evolving from fixed frame-integrated mounts to replaceable designs used across most modern road, mountain, gravel, and touring bikes.

Today’s derailleur hangers come in hundreds of shapes, often frame-specific, and play a critical role in drivetrain function—especially as shifting tolerances have become more precise with 11- and 12-speed systems, leading to innovations like the SRAM UDH (Universal Derailleur Hanger) to simplify compatibility and improve reliability across brands.

How does a bike derailleur hanger work?

A bike derailleur hanger works as the mounting interface between the derailleur and the bike frame, ensuring precise alignment so the derailleur can shift the chain smoothly across gears. It is designed to bend or break under impact, acting as a sacrificial component to protect the derailleur and frame from damage, and is commonly replaceable on modern bikes.

How does a bike front derailleur hanger work?

A bike front derailleur hanger (also called a braze-on tab or clamp-on mount) provides a fixed mounting point on the seat tube for the front derailleur, ensuring the derailleur cage aligns properly with the chainrings for smooth front shifting. The hanger keeps the derailleur in position relative to the crankset, and its placement affects shifting quality, cage height, and angle—which is especially important in multi-ring setups.

How does a bike rear derailleur hanger work?

A bike rear derailleur hanger attaches to the rear dropout and serves as the connection point for the rear derailleur, ensuring it stays in line with the cassette for accurate indexing. It also absorbs force in case of impact or crash, preventing damage to the frame or derailleur, and can be realigned or replaced to maintain drivetrain performance.

Why are there so many derailleur hangers?

There are so many derailleur hangers because bike frames vary widely in design, geometry, axle standards, dropout shapes, and materials, and each brand often creates a proprietary hanger to match their specific frame structure. Manufacturers design unique hangers to fit carbon, aluminum, or steel frames, accommodate different axle types (quick release vs. thru-axle), and ensure the rear derailleur aligns correctly for smooth shifting—leading to hundreds of distinct models across the cycling industry.

Do I need a derailleur hanger?

Yes, you need a derailleur hanger if your bike uses a rear derailleur and has a frame designed to accept one, as it acts as the critical interface between the derailleur and the frame. Without it, you cannot mount or align the derailleur properly unless your frame has an integrated hanger, which is rare on modern bikes.

Do all derailleurs need a hanger?

Yes, all rear derailleurs need a hanger if they are of the modern derailleur-mounted type, because the hanger provides the mounting point and alignment necessary for proper gear shifting. But some older or internal hub gear systems (like Rohloff or Shimano Nexus) do not use traditional derailleur hangers, as they don’t use a rear derailleur at all.

Bike derailleur hanger diagram

A bike derailleur hanger is a small but crucial part that connects the derailleur to the bike frame, allowing precise alignment for smooth and reliable shifting. It is especially important for rear derailleurs, where shifting tolerances are tight, and derailleur movement must stay in line with the cassette. The hanger is designed to absorb impacts, protecting both the derailleur and frame in crashes, and is often replaceable for easy maintenance. While front derailleur hangers are usually fixed or clamp-on mounts for positioning the front derailleur over the chainrings, rear derailleur hangers vary widely in shape and standard.

Are bike derailleur hangers universal?

No, bike derailleur hangers are not universal because they are designed to fit specific frame geometries, dropout shapes, and axle standards, and each bike brand—and often each model—uses its own hanger shape. This leads to hundreds of unique designs, although SRAM’s UDH (Universal Derailleur Hanger) is helping to create a standard on newer frames.

Are bike front derailleur hangers universal?

No, bike front derailleur hangers are not universal because they depend on the frame’s seat tube diameter, shape, and mounting type—either braze-on or band-on clamp sizes like 28.6 mm, 31.8 mm, or 34.9 mm. Compatibility varies by bike type, drivetrain setup (1x, 2x, 3x), and front derailleur brand.

Are bike rear derailleur hangers universal?

No, bike rear derailleur hangers are not universal because they must match the exact frame interface, dropout design, and rear axle type, which vary widely across brands and models. Although some newer bikes support UDH (Universal Derailleur Hanger), most still require specific hanger designs.

What are the types of bike derailleur hanger?

The types of bike derailleur hanger include classifications such as sorted by front and rear types, mounting type, drivetrain type, bike type, and manufacturing style, because each of these factors influences compatibility, performance, and frame integration. Sorting them this way helps cyclists, mechanics, and manufacturers ensure proper fitment, shifting accuracy, and durability across a wide variety of bikes and drivetrain systems.

Bike derailleur hanger sorted by front and rear types

Bike derailleur hangers sorted by front and rear types include front derailleur hangers (braze-on or clamp-on) and rear derailleur hangers (standard or direct-mount), because each plays a specific role in aligning the derailleur for precise shifting performance depending on its drivetrain location.

1. Bike front derailleur: Uses either a braze-on mount welded to the seat tube or a band-on (clamp-on) hanger that fits around the tube, positioning the derailleur cage correctly over the chainrings for smooth and accurate front gear changes.
2. Bike rear derailleur: Attaches to the rear dropout via a replaceable hanger (standard or direct-mount), keeping the derailleur aligned with the cassette and serving as a sacrificial component to protect the frame and derailleur during impacts.

Bike derailleur hanger sorted by mounting type

Bike derailleur hangers sorted by mounting type include direct-mount and hanger-mount (standard) types, because each defines how the rear derailleur connects to the frame and affects shifting alignment, wheel clearance, and compatibility with different drivetrain systems.

1. Bike direct-mount derailleur hanger: Bolts the derailleur directly to a dedicated frame mount, eliminating the traditional B-link to provide increased stiffness, better chainstay clearance, and easier wheel removal, commonly used on modern MTB and gravel bikes.
2. Bike hanger-mount (standard) derailleur hanger: Attaches to a separate replaceable hanger bolted to the frame’s dropout, offering broad compatibility and protection, and remains the most common setup across road, touring, and traditional MTB bikes.

What are the benefits of direct mount derailleur hanger?

The benefits of a direct mount derailleur hanger include increased stiffness, improved shifting precision, easier rear wheel removal, better chainstay clearance, and simplified frame compatibility for wide-range drivetrains.

1. Increased stiffness: The direct mount design eliminates the B-link, creating a more rigid connection between the derailleur and frame, which improves shift consistency—especially under load.
2. Improved shifting precision: A stiffer mount minimizes derailleur flex and misalignment, resulting in crisper and more accurate gear changes across the cassette.
3. Easier rear wheel removal: With the derailleur positioned slightly rearward, it frees up space at the dropout, making it faster and more convenient to remove and install the rear wheel.
4. Better chainstay clearance: Direct mount hangers position the derailleur farther back and lower, reducing the chance of chain-to-stay contact on wide-range MTB or gravel drivetrains.
5. Simplified frame compatibility: Direct mount standards (like SRAM UDH) support modern frame designs and wide gear ranges, making it easier for manufacturers and riders to maintain drivetrain consistency across builds.

Direct mount vs hanger mount derailleur hanger

Direct mount vs. hanger mount derailleur hangers are often compared because they represent two different ways of attaching the rear derailleur to the bike frame—each with unique effects on stiffness, shifting performance, frame compatibility, and ease of maintenance. As drivetrain technology and frame standards evolve, understanding the differences helps riders choose the right system for their riding style, bike type, and drivetrain setup.

Bike derailleur hanger sorted by drivetrain type

Bike derailleur hangers sorted by drivetrain type include those made specifically for Shimano, SRAM, Campagnolo, microSHIFT, and other drivetrain systems, because each brand uses different derailleur mounting standards, actuation ratios, and cassette spacing, which require precise alignment and compatibility with the corresponding hanger or frame design.

1. Bike Shimano derailleur hanger: Designed to fit Shimano’s derailleur mounting dimensions and actuation system, often supporting Shadow RD+, Di2, and mechanical drivetrains with standard hanger or direct-mount compatibility.
2. Bike SRAM derailleur hanger: Made for SRAM’s mechanical and electronic (AXS) systems, often requiring Exact Actuation or X-Horizon geometry, and increasingly supporting UDH (Universal Derailleur Hanger) for modern MTB and gravel bikes.
3. Bike Campagnolo derailleur hanger: Tailored to Campagnolo’s unique mounting interface and indexing, compatible with EPS and mechanical systems, typically used on high-end road racing frames.
4. Bike microSHIFT derailleur hanger: Compatible with Shimano-style hangers due to similar mounting geometry and cable pull, making it a common choice for entry-level and commuter bikes that use Shimano-style dropouts.
5. Bike L-TWOO derailleur hanger: Often designed to match Shimano-style interfaces for easy OEM integration, with compatibility aimed at budget builds and hybrid bikes, using standard hanger mounts.

Can Sram derailleur use direct mount hanger?

Yes, a SRAM derailleur can use a direct mount hanger if it is specifically designed to be compatible with the UDH (Universal Derailleur Hanger) standard, which SRAM developed to simplify hanger design and improve compatibility. But most traditional SRAM rear derailleurs—especially older models—are intended for standard hanger mounts with a B-link, so using them with a direct mount hanger would require a compatible frame and the correct derailleur model.

Can Shimano derailleur use direct mount hanger?

Yes, Shimano derailleurs can use a direct mount hanger if they are part of Shimano’s direct mount-compatible groups, such as certain Deore, SLX, XT, or XTR MTB models, which feature a removable B-link to attach directly to the frame. But not all Shimano derailleurs are direct mount-ready, so the model must specifically support direct mount and the frame must include a compatible hanger interface.

Can Shimano derailleur use UDH hanger?

No, Shimano derailleurs cannot use a UDH hanger directly because UDH (Universal Derailleur Hanger) is a SRAM-developed standard intended to work with UDH-specific SRAM derailleurs. But Shimano derailleurs can still be used on UDH-compatible frames if the frame manufacturer includes a standard hanger adapter alongside the UDH mount.

Bike derailleur hanger sorted by bike type

Bike derailleur hangers sorted by bike type include those for road, mountain (MTB), gravel, BMX, touring, e-bike, and folding bikes, because each type of bike has unique drivetrain demands, frame geometries, and gear setups that require different derailleur hanger designs for optimal shifting performance and compatibility.

1. Road derailleur hanger: Designed for close-ratio cassettes and lightweight frames, it positions the derailleur for precise shifting and minimal drag, common in racing and endurance road bikes.
2. Mountain derailleur hanger: Built to handle wide-range gearing and rough terrain, it often includes direct mount or UDH compatibility and allows for long cage derailleurs with clutch systems.
3. Gravel derailleur hanger: Balances road and MTB characteristics, often supporting 1x or 2x drivetrains with wide-range cassettes, and commonly built with direct mount or UDH options for rugged versatility.
4. BMX derailleur hanger: Rare, as most BMX bikes are single-speed, but geared freestyle or race models may use a basic, durable hanger for limited gear setups.
5. Touring derailleur hanger: Supports triple chainring and long cage derailleurs, designed to handle heavy loads and extended gear ranges, prioritizing durability and serviceability.
6. E-bike derailleur hanger: Reinforced to handle increased torque and chain tension from pedal-assist motors, often made thicker and more robust for extra strength and stiffness.
7. Folding bike derailleur hanger: Compact and specific to folding frame geometries, it allows for small wheel compatibility and often uses simplified derailleur systems to fit limited space.

Bike derailleur hanger sorted by manufacturing style

Bike derailleur hangers sorted by manufacturing style include CNC-machined and 3D-printed types, because different production methods impact the hanger’s precision, strength, cost, and repairability, which are crucial for shifting accuracy and frame protection.

1. CNC-machined derailleur hanger: Made from a solid block of aluminum or alloy using computer-controlled cutting tools, offering high precision, excellent strength, and consistent quality, commonly used in performance and OEM applications.
2. 3D-printed derailleur hanger: Manufactured using additive processes like metal or polymer printing, allowing for rapid prototyping or custom designs, though often used in emergency replacements, unique builds, or low-volume production due to varying material durability.

How do you choose a bike derailleur hanger?

You can choose a bike derailleur hanger by considering key factors such as frame compatibility, derailleur brand, mounting type, drivetrain system, axle type, material, and availability, as each ensures the hanger fits precisely and supports accurate shifting.

1. Frame compatibility: You can identify your bike’s brand, model, and year to ensure the hanger fits the specific frame design, as hangers are often unique to each frame.
2. Derailleur brand compatibility: You can match the hanger to the drivetrain brand (Shimano, SRAM, Campagnolo, etc.), especially if your setup uses direct-mount or UDH standards.
3. Mounting type: You can determine whether your bike uses a standard hanger, direct mount, or UDH, by inspecting the dropout and derailleur attachment point.
4. Drivetrain system: You can choose a hanger that supports your drivetrain configuration, such as wide-range cassettes or 1x/2x setups, which may require specific derailleur positioning.
5. Axle type: You can confirm if your bike has a quick release or thru-axle, since the hanger shape and threading can differ between axle systems.
6. Material: You can choose between aluminum, steel, or carbon composite hangers depending on whether you prioritize weight, stiffness, or impact resistance.
7. Availability: You can ensure the hanger is easily replaceable by checking common sources like Wheels Manufacturing or your bike brand’s official catalog.

How do you choose a front bike derailleur hanger?

You can choose a front bike derailleur hanger by determining whether your frame uses a braze-on tab or requires a band-on (clamp-on) style, which depends on the seat tube diameter—commonly 28.6 mm, 31.8 mm, or 34.9 mm. You should also ensure it matches your drivetrain configuration (1x, 2x, or 3x) and the front derailleur model, so that the cage aligns correctly with the chainrings for precise shifting.

How do you choose a rear bike derailleur hanger?

You can choose a rear bike derailleur hanger by identifying your bike frame’s brand, model, and year, as most hangers are frame-specific and not interchangeable. Additionally, ensure the hanger is compatible with your derailleur mounting type (standard, direct mount, or UDH) and supports the proper alignment and shifting for your cassette size and drivetrain system.

How do I know what derailleur hanger I need?

You can know what derailleur hanger you need by identifying your bike frame’s brand, model, and production year, as most derailleur hangers are frame-specific and designed to match the shape of your rear dropout. You should also check the drivetrain manufacturer (e.g., Shimano, SRAM, Campagnolo) to ensure the hanger supports the proper mounting interface and derailleur alignment, and reference your frame on trusted databases like Wheels Manufacturing or DerailleurHanger.com to find the exact replacement.

How do you install a bike derailleur hanger?

You can install a bike derailleur hanger by following these steps: identify the correct hanger, clean the mounting area, align the hanger with the dropout, thread and tighten the bolt, check alignment with a hanger alignment tool, and reinstall the derailleur.

1. Identify the correct hanger: Match the hanger shape, hole placement, and thickness with your bike frame’s brand, model, and year to ensure proper fit and compatibility.
2. Clean the mounting area: Remove dirt, grease, or debris from the dropout and bolt threads to allow for secure contact and precise alignment.
3. Align the hanger with the dropout: Seat the hanger flush against the dropout, ensuring the holes line up and the hanger sits evenly without gaps.
4. Thread and tighten the bolt: Insert the bolt and tighten it using a 5mm Allen key (or required tool) to the recommended torque—usually between 8–10 Nm—for a solid, vibration-resistant hold.
5. Check alignment with a hanger alignment tool: Use a derailleur hanger alignment gauge to confirm that the hanger is straight and properly aligned with the cassette.
6. Reinstall the derailleur: Bolt the rear derailleur back onto the hanger and proceed with any necessary adjustments like limit screws, cable tension, and indexing.

How do you install a front derailleur hanger?

You can install a front derailleur hanger by either attaching a band-on clamp around the seat tube (matching the correct diameter: 28.6, 31.8, or 34.9 mm) or bolting a braze-on adapter if your frame supports it. Make sure the hanger is positioned so the derailleur cage aligns parallel with the chainrings and sits 1–3 mm above the largest chainring for precise shifting.

How do you install a rear derailleur hanger?

You can install a rear derailleur hanger by aligning it with the frame’s rear dropout and tightening the hanger bolt using a 5 mm Allen key to the recommended torque (usually 8–10 Nm). After installation, use a hanger alignment tool to ensure the hanger is perfectly straight to maintain accurate derailleur indexing.

How do you replace a rear derailleur hanger?

You can replace a rear derailleur hanger by first removing the rear derailleur and any axle or wheel that blocks access, then unbolting the damaged hanger from the dropout. Install the new hanger by aligning it correctly, tightening it to spec, and checking for alignment before reinstalling the derailleur and adjusting shifting.

How do you adjust bike derailleur hanger?

You can adjust a bike derailleur hanger by addressing several key factors: checking for misalignment, using a hanger alignment tool, correcting the angle, ensuring proper torque, and verifying derailleur positioning for optimal shifting performance.

1. Check for misalignment: Visually inspect the derailleur hanger from behind the bike to see if it’s bent inward or outward in relation to the cassette cogs.
2. Use a hanger alignment tool: Thread the alignment gauge into the hanger and measure its distance from the rim at multiple clock positions to identify any lateral deviation.
3. Correct the hanger angle: Gently bend the hanger using the alignment tool until it maintains a consistent distance from the rim all the way around.
4. Tighten the hanger bolt: Ensure the hanger is securely fastened to the dropout using the correct torque specification, typically between 8–10 Nm.
5. Verify derailleur positioning: Reinstall the rear derailleur and test shift across the cassette to confirm smooth transitions and accurate indexing.

How do you align derailleur hanger?

You can align a derailleur hanger using a derailleur hanger alignment tool, which threads into the hanger and allows you to check and correct its position relative to the rim at multiple points (e.g., 12, 3, 6, and 9 o’clock). By gently bending the hanger with the tool until all measured points are equidistant from the rim, you ensure the derailleur runs straight for smooth and precise shifting across the cassette.

How do you fit a mech hanger?

You can fit a mech hanger by aligning it flush with the frame’s rear dropout, then inserting and tightening the hanger bolt using a 5 mm Allen key or the required tool to the recommended torque (usually 8–10 Nm). After installation, confirm it is properly seated and aligned before attaching the rear derailleur, as even slight misalignment can cause poor shifting and drivetrain wear.

How do you fix a derailleur hanger on a bike?

You can fix a derailleur hanger on a bike by addressing several key factors: identifying the damage, removing the hanger, cleaning the dropout, installing or replacing the hanger, aligning it with a hanger alignment tool, and checking derailleur function, using tools such as a 5 mm Allen key, torque wrench, and alignment gauge.

1. Identify the damage: Check for visible bends, cracks, or misalignment in the hanger that may be causing shifting issues or drivetrain noise.
2. Remove the hanger: Use a 5 mm Allen key (or required tool) to unbolt the damaged hanger from the frame’s dropout.
3. Clean the dropout surface: Wipe down the mounting area to remove dirt or debris for proper seating of the new or realigned hanger.
4. Install or replace the hanger: Fit the hanger snugly against the dropout and tighten the bolt to the manufacturer’s recommended torque (typically 8–10 Nm).
5. Align the hanger: Use a derailleur hanger alignment tool to check and correct its position, ensuring it’s centered and aligned with the cassette.
6. Check derailleur function: Reinstall the rear derailleur and test shifting through the gears to verify smooth operation and correct indexing.

What should I do if my derailleur hanger is bent or broken?

You should replace a broken derailleur hanger immediately and realign a bent one using a hanger alignment tool to avoid poor shifting, chain misalignment, or drivetrain damage. Continuing to ride with a misaligned hanger can damage your rear derailleur, cassette, or chain, and degrade shifting performance.

Why my rear derailleur hanger keep breaking?

Your rear derailleur hanger keeps breaking because it is absorbing excessive force from impacts, crashes, chain jams, or misaligned shifting, which it’s designed to do as a sacrificial part to protect your frame and derailleur. Repeated breakage may also indicate underlying issues such as a bent dropout, incorrect limit screw settings, or an improperly adjusted derailleur placing constant stress on the hanger.

How do you tell if rear derailleur hanger is bent?

You should visually inspect the hanger from behind the bike to see if it appears twisted or misaligned in relation to the cassette cogs, or use a derailleur hanger alignment tool for precise measurement. Signs include inconsistent shifting, chain skipping, or derailleur rubbing across gears.

How do you straighten a bent derailleur hanger?

You should thread a derailleur hanger alignment tool into the hanger and gently adjust it until its measured distance from the rim is consistent at multiple points (12, 3, 6, and 9 o’clock). Proper realignment ensures the derailleur sits correctly beneath the cassette for smooth and reliable shifting.

What causes a rear derailleur hanger to break?

That derailleur hangers break primarily due to impacts, crashes, chain drops, or excessive drivetrain tension, especially during improper shifting under load. They’re intentionally designed as sacrificial parts to protect the derailleur and frame, especially in aluminum and carbon frames.

How long do bike derailleur hangers last?

Bike derailleur hangers can last anywhere from 5,000 to 20,000 km (3,000 to 12,000 miles) depending on riding conditions, impact frequency, drivetrain setup, and material quality. Hangers made from soft aluminum may bend more easily but protect your drivetrain, while stronger steel hangers can last longer but are less forgiving in crashes.

How much do you replace a rear derailleur hanger?

It costs around USD $20–$40 / EUR €20–€35 / GBP £18–£30 to replace a rear derailleur hanger, depending on the bike brand, material, and availability. Labor at a shop may add USD $10–$25, especially if hanger alignment is included with the service.

How often do you replace derailleur hanger?

You should replace a derailleur hanger whenever it is visibly bent, cracked, or broken, which may occur every 6,000–12,000 km (3,700–7,500 miles) under normal use, or immediately after a crash. Regular inspections—especially after off-road rides or drivetrain issues—help prevent damage to more expensive components.

Bike derailleur hanger brands and manufacturers

Bike derailleur hangers may be small components, but they are essential for rear derailleur alignment and drivetrain performance. While many bike manufacturers produce proprietary hangers for specific frames, there are also dedicated hanger brands and aftermarket specialists that offer replacements for a wide range of bike types. Each brand brings unique strengths in compatibility, precision machining, and innovation, helping riders maintain smooth shifting and protect their frames from damage.