All About Derailleur Hangers: Types, Function, and Tips for Cyclists

Derailleur hangers are small metal pieces that connect the rear derailleur to the bicycle frame. Their function is critical: they act as a mechanical fuse in the event of a crash or impact, bending or breaking to prevent more serious damage to the frame or derailleur.

Although at first glance they all look the same, in reality there are hundreds of different models with specific shapes, thicknesses, mounting systems and dimensions depending on the brand, model and year of the frame. This variety makes it impossible to stock all replacements at events or races.

Therefore, if you are going to participate in a race or cycling event, it is very important to carry at least one spare derailleur hanger specific to your bike. We cannot carry every variant, and a broken hanger without a replacement could mean immediate withdrawal from the race.

1. Types according to derailleur mounting system

• Hook Type (with integrated hook): the derailleur has a hook that attaches directly to the dropout without needing a separate hanger.
• Standard Mount: traditional hanger bolted to the frame, common and easy to replace.
• Direct Mount: the derailleur mounts directly to the frame, offering better stiffness and alignment. Requires a compatible frame or adapter.

2. Newer and more universal standards

SRAM Universal Derailleur Hanger (UDH): designed to be a standard across frames and simplify replacement. Its pivoting design helps prevent damage to the derailleur or frame.

3. Types according to rear axle system

• Quick Release (QR): for traditional 9–10 mm quick release axles.
• Thru Axle: for larger diameter thru axles (12 mm, etc.), more common in modern MTB bikes.

4. Variety by frame or brand

Each manufacturer and model may use a specific hanger, resulting in a huge variety. Some well-known brands that offer compatible replacements include Wheels Manufacturing, Pilo, Marwi, among others.

5. How to find the correct hanger?

1. Identify if your bike uses QR or Thru Axle.
2. Determine whether the mounting system is standard or direct.
3. Check how many bolts it uses and whether it mounts inside or outside the frame.
4. Use image-based databases (WheelsMfg, Pilo, etc.).
5. And above all: the best option is to go to the store where you bought your bike and ask for a specific replacement hanger. They will know exactly which one fits your model.

Practical advice for races or events

If you are going to participate in a race or cycling event, bringing a spare derailleur hanger is highly recommended. Due to the wide variety of models, it is unlikely you will find a compatible one if yours breaks during the event. The best option is to go to the store where you bought your bike and get a specific spare hanger. This way, you can avoid dropping out of the race due to a preventable mechanical issue.

Conclusion: the derailleur hanger is a unique part, specifically designed for each bike frame. Its role as a mechanical fuse makes it an essential component, and its variety prevents the existence of a universal replacement. If you plan to race or go on a demanding ride, don’t think twice: carry a hanger specific to your bike. It could be the difference between finishing or abandoning the event due to a breakdown.