Although replacing a derailleur hanger is not difficult, it must be carried out correctly to have the smooth shifting you anticipate from your derailleur.
Furthermore, in many circumstances, a broken derailleur hanger indicates a problem with the transmission, such as a bent or incorrectly fitted rear derailleur, a damaged or too short-chain, etc. New hangers can breakfast if they are not checked and fixed promptly after installation.
Whenever possible, leave your ebike in the hands of a competent technician. If not, be sure you follow the guidelines listed below.
You will only need a few tools to complete the installation of a derailleur hanger. You will need the following materials:
- Hexadecimal keys (for installing the derailleur hanger and derailleur)
In addition, the following items are required for the installation of the chain and the adjustment of the derailleur:
- A tool with a chain (for splitting the chain)
- Screwdriver with a Philips head (for adjusting the derailleur)
How to repair the derailleur hanger
Preparedness and removability
The derailleur hanger is often damaged due to a collision with the derailleur or another object. However, be sure that none of the other critical components of your ebike has been damaged. Before proceeding, check for damage to the frame, derailleur, chain, shifter cable, and rear wheel. If you find any, repair it before continuing.
Carefully remove any residual components of the old derailleur hanger from the derailleur hanger. Remove the back wheel to allow easier access to the derailleur hanger, and then remove the derailleur from the hanger using a hex or Torx key, depending on the kind of derailleur you have. It is necessary to use a minor hex key to remove the derailleur hanger from the frame; in my instance, this is a 4mm hex key. Take care not to damage the frame, and clean the derailleur hanger mount when you're through.
Install the new derailleur management system.
Take your new derailleur hanger and apply some Loctite to the threads of the screws since you won't be able to properly tighten the screws in the aluminium derailleur hanger unless you use a torque wrench. Then, with the derailleur hanger in position, screw the derailleur hanger into place on the frame. This part should only be used one way, with the notch positioned towards the ebike's rear. It is essential to avoid cross-threading and not overtighten the bolts; about 2Nm is sufficient.
It is simple to install the derailleur hanger but avoid overtightening the screws.
Configuration of the derailleur and the wheel
When you have a standard dropout hanger, you may now install the derailleur without any problems. If you have a direct mount derailleur hanger, you will need to remove the B-link from the derailleur if you haven't already done so before continuing. With a hex or Torx key, secure the derailleur to the derailleur hanger and tighten it to around 8-10Nm of tension. You should not have any gaps between the B-link and the notch of the derailleur hanger if you have a B-link. In certain circumstances, the b-screw must contact the derailleur hanger. Turn the derailleur a little to the left or right so that the b-screw applies some force to the notch in the derailleur hanger, as shown.
Now that the derailleur has been mounted, switch it to the setting to lessen its resistance. Not all derailleurs have this feature, but for Shimano's Shadow Plus derailleurs and SRAM derailleurs with Cage Lock, you must first engage the clutch mechanism in the off position and then engage the clutch mechanism in the locked position. Now that the back wheel has been installed, we can proceed to the following phase, which is installing the chain.
Placing the B-Link against the notch of the derailleur hanger will ensure proper alignment.
Deliver and install the chain
I'll go through the fundamentals of chain installation before we get started. The article How to Replace a Mountain Ebike Chain has additional in-depth information on the installation and removal of chain links and the many forms of connection and chain length.
The chain that I'm using to attach the cassette is used and worn, which is consistent with the condition of the chainring and cassette. The new chain is recommended if the wear on your chainring and cassette has not yet reached its maximum capacity. A new chain on old chainrings, on the other hand, is not a good solution since it reduces performance and increases chain wear. The master link, a two-part outer chain link that makes it much simpler to install and remove the chain (and maybe reused depending on the kind of chain link you purchase), is used to join the chain links together.
By default, two links are added to the chain; however, when employing a master link, only one link is added to the chain's length.
Take the chain tool and set it above the centre of the pin, then use it to push the pin out of the chain until it is entirely out. Things take a lot of effort to get started. When the pin has been removed, remove the tool and reinstall the chain in the proper position. The chain should be wound around the chainring and cassette, passing through the rear derailleur and if you have one, the front derailleur. Pay close attention to the rear derailleur since the chain must travel in a straight line between the guide pulley and tension pulley to avoid rubbing on the tab of the derailleur cage there.
Place one section of the master link on each end of the chain and pull the two ends together to complete the chain. Ensure that the master link's two sides are aligned, and then press the two sides together. Apply stress to the chain to ensure that the master link is securely fastened. Positioning the master link between the cassette and chainring, applying the rear brake, and turning the crank will provide additional force if the link is damaged or worn.
To complete the process, you must engage the clutch mechanism of the derailleur once again. Depending on your derailleur, you may need to turn on the clutch mechanism or turn off the Cage Lock feature.