How To Install A Rear Derailleur On A Mountain Bike?

Looking to install a rear derailleur on your mountain bike. There are a variety of reasons you want or need to change the rear derailleur from being out biking and your derailleur not shifting through the gears properly or you need a better derailleur.

The more durable the derailleurs the better. The rear derailleur is an important component of a mountain bike as it is the mechanism that moves the chain from one gear to another. A bike can have two derailleurs with one for the rear and the other for the front.

In this post, we will go through installing a rear derailleur, and you can go biking with confidence. Let’s get started!

Read more on common questions asked

Types Of Derailleurs

As we know that the main job of a derailleur is that changes the gears, by de-railing the chain and then pulling it off one cog or sprocket onto another. A bike can have only one rear derailleur, or both a rear derailleur and a front derailleur.

There are also front and rear derailleurs, especially for MTB and there are derailleurs for road bikes.

Mountain Bike Derailleurs

The rear derailleur comes in 3 different types. These are as follows.

  • Standard derailleur – This is the traditional one where the cable tension is released and the derailleur shifts the chain to a smaller cog, which happens to be a higher gear.
  • Low-normal derailleur – Releasing cable tension moves the derailleur in the opposite, or backward direction.
  • Electronic derailleur – Mainly used on road bikes, is powered by a battery.

Checking Derailleurs Regularly

The derailleurs should be inspected regularly. A properly adjusted derailleur shouldn’t be making any real noise. If there is noise coming from the derailleur when shifting gears, the derailleur may need an adjustment.

If after the adjustment, the noise stills persists, it may be time to replace the derailleur. It is also worth going to the local bike shop to help to identify the problem and fix it.

There are others things to look out for when inspecting your derailleur, such as.

  • That the chain does not come off.
  • That the chain should line up smoothly with each chainring and be rubbing against the chain.
  • Any debris in and around the chain and the derailleur.
  • That the derailleur cage does not rub the crankarm.

What Can Cause A Rear Derailleur To Break?

Derailleurs can break, there are a few common causes that break derailleurs. These are as follows.

  • Over shifting into the spokes, happens because your low limit screw was improperly set, which allowed the derailleur to move too far beyond the largest cog.
  • The hanger has been bent from an accident or letting the bike fall over on its right side.
  • The derailleur was built with a defect or it was a cheap derailleur, with the derailleur there was an area that was weak, and even a moderate vibration of the ride breaks the derailleur.
  • Simply it is old and cumulative wear and tear caused it to fail under those conditions.
  • Debris can get got in between the chain and the derailleur, which can break the derailleur.

What Tools You Will Need

There are a couple of tools and materials needed for installing a rear derailleur. These are as follows.

Install A Rear Derailleur On A Mountain Bike

Before installing a new rear derailleur you need to check if you need to replace the old derailleurs. Make sure the derailleurs jockey wheels are not broken in any way.

Let’s get started installing a new rear derailleur.

Remove The Old Rear Derailleur

  • The first step is to remove the old rear derailleur. Put your bike into a bike stand. And shift the chain into the smallest sprocket.
  • Now you need to disconnect the shift cable. Do this by pulling off the shift cable’s end cap and then loosening the cable pinch bolt. Remove the shift cable from the derailleur.
  • Now you need to remove the chain from the derailleur. Find the master link in the chain as this is a quick-release link that makes it easier to connect and disconnect the chain without the need for a chain tool. You will need a chain tool if your chain does not have a master link.
  • Now to remove the rear derailleur, going counterclockwise, you can unthread the derailleur’s mounting bolt.
bike inspections

Install The New Rear Derailleur

  • The first step to installing the new derailleur is a quick visual inspection that the current derailleur hanger is in good shape. Just ensure there is that the threads are not damaged and there is no other obvious damage.
  • Now mount the derailleur to the mounting bolt going anti counterclockwise. Then fully tighten the mounting bolt.
  • Now you need to put the chain back on. So, do so.
  • Now put the shift cable back into the derailleur, then pull it tight and tighten the anchor bolt so the cable flattens.

Adjustment And Finishing

  • Installing a rear derailleur doesn’t stop in replacing the old with the newer ones. Instead, there is an additional step that you should take, and that is the adjustment step.
  • In adjusting the rear derailleur, you limit the lower and higher ends of the screws so you prevent your derailleurs to move more than the limits you have set through adjusting the chains and links.
  • Finally, do a test that everything is working as it should. If everything is smooth you have done the job properly.

Wrapping Up

Finally, I hope this article covering how to install a rear derailleur was helpful. Making sure your derailleur is working properly is important. Accidents do happen that can break your derailleur and sometimes the derailleur just breaks from wear and tear. Replacing the rear derailleur is a fairly straightforward process.

And that’s it for now! I’d love it if this post on how to install a rear derailleur on a mountain bike was helpful to you. Let me know if you have any questions and let me know if there is more to add.

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Rear Derailleur On A Mountain Bike