Derailleurs are an expensive component, and you don’t want to damage them! In this article we will talk about a replaceable derailleur hanger, and how it is made to save you money, work, and even the whole bike.

So what is a derailleur hanger? A Derailleur Hanger is a small piece of metal found at the end of your frame and it attaches the derailleur to the bicycle frame. This piece is generally affordable, made out of aluminum, and is very important to your bike. Derailleur Hangers are can also be referred to as gear mech hangers, dropouts and even frame savers.

Why do bicycles have detachable derailleur hangers?

You can see the hanger is the black piece between the white frame, and the derraileur

Bicycles, more specifically mountain bikes have derailleur hangers to protect the derailleur itself! When an impact happens to the derailleur, the weakest point is what is going to break, so the hanger is engineered to be the first thing to fail, rather than the derailleur itself.

It is better to have a cheap component break, rather than one of the most expensive components on the bike, being the derailleur.

What happens if you don’t have a detachable derailleur hanger?

Not all bikes have detachable derailleur hangers (like the Genesis Incline I had for a bit)! So what happens if an impact happens to a derailleur on those bikes?

The most common thing, is that the derailleur can be bent, which is difficult, because it is hard to know if a derailleur is bent just by looking at it. Instead you will notice your bike not shifting correctly, or shifting to wrong gears.

Another, worse thing that can happen, is that the derailleur bends too far and can actually break the frame of your bicycle. Unfortunately if this happens, the bike will be completely out of commission. For less expensive bikes, this can mean needing to purchase a new one, for more expensive bike setups you can salvage the remaining parts and install them on a newly purchased frame.

How do you replace a derailleur hanger?

The big benefit of derailleur hangers, is the ease of replacement! If you notice that your hanger is no longer straight, you can purchase a new one, remove the derailleur from your bike and install the new one.

All you need to do this is have an available hex wrench, some cleaner, and some grease. You will just remove the rear bike wheel, use the hex wrench to remove the derailleur. From here, you will clean and grease the frame where you are installing the hanger, and then do everything backwards from what you just did.

The whole process should only take a couple minutes, and you are back on the trail!

Can you align a derailleur hanger?

While you can technically temporarily align or straighten a damaged derailleur hanger, this should only be done to get you back to where you need to be. Once one of these is bent, it will never be quite right, and due to the low cost of replacement, it is worth getting a new one and installing it.

If you are in the case where you need to straighten it out, you will want to lay it on a flat hard surface and hammer it out.

Should you carry a spare derailleur hanger?

It is never a bad idea to have a spare derailleur hanger on hand in case of emergencies. You never know what could happen to your current one, and this would be perfect for the situation where you have bent it out of shape or need an emergency replacement.

When you have a spare derailleur hanger it can save you time, and headache.

For most people, Derailleur Hangers are an afterthought- they don’t even think about them until there’s a problem and then suddenly realize that this could have saved a lot of heartache if they had just purchased one.

Is a dropout and a derailleur hanger the same thing?

A dropout and a derailleur hanger are not necessarily the same thing. While they are nearby to each-other, they serve different purposes. A dropout on a bike is a small metal piece that attaches the wheel to the frame. Derailleur hangers, on the other hand, are a mounting point for Derailleurs, not the wheel itself.

For bikes that don’t have detachable derailleur hangers, these two components will be on the same plate, however if the hanger is detachable, the hanger will be a separate component to the dropout.

Frequently Asked Questions

How much does a derailleur hanger cost?

Most of the time, derailleur hangers cost about $15-$20 which can vary depending on the type and quality of the hanger. However I have also seen some as low as $6. While that still may seem like a lot for a small piece of metal, it is way better than replacing a $100 derailleur, or worse yet the frame.

How do I know if my derailleur hanger is bent?

You will know your derailleur hanger is bent by looking at the derailleur. If it is not pointing straight, then that would mean your hanger needs to be replaced. The easiest way to tell this is by standing in the front of your bike facing to the back, and lining up the derailleur with the frame of your bike, if it doesn’t look straight, it is time to replace.

How do you align a derailleur hanger without tools?

Without any tools, there really isn’t any great way of doing this! However putting the hanger on some cement and then hitting it with a large rock might just do the trick. That said, it might just be a better idea to keep a tool kit on you.

Are all replaceable derailleur hangers the same?

All derailleur hangers are not the same, while most look similar, there might be slight differences! Make sure to get the right one for you, by verifying that it is the same brand as your bike, and meant for the model as well.


Alright, now we have learned exactly what a derailleur hanger is, and why you should probably be have one available at all times while riding, especially on a mountain bike! If you are planning on going for a long trip on your bike (maybe even bike-packing) you should be thinking about keeping one of these on hand.