Replacing a derailleur hanger is not a complex operation, but it must be done correctly to get the perfect shifting you expect from your derailleur.
In addition, in many cases, a broken derailleur hanger is a sign of a problem in the transmission: rear derailleur bent or improperly adjusted, chain damaged or too short ... If you don't check and do not solve the problems, new hanger could break quickly.
Don't hesitate to entrust your bike to a professional mechanic. Otherwise be sure to follow the tips below.
- Before installing a new derailleur hanger, check the state of dropout.
- If the area you seem damaged, do not install new hanger and go to a professional mechanic who will analyze the state of the frame.
- If the state of the area you seem okay, then clean and apply a light film of grease to minimize noise or “creaking.”
- Apply Loctite on the screws and mount the bracket into place by tightening the screws reasonably (warning: overtightening can damage the threads of the hanger).
- Check to make sure that the hanger screw ends do not contact or interfere with the rear sprocket or chain. File the protruding screw end if necessary..
- Re-attach the rear derailleur and check derailleur alignment using the following diagram. If, with a new hanger you don't get an alignment at 90 °, don't get a new hanger and go to a professional mechanic who will analyze the state of the frame.
Then check the inboard and outboard limit adjustment and the index adjustment.
New hanger can be different in thickness of origin, also make sure to adjust the quick release wheel so that it is tight enough.
Derailleur replacement hanger is now complete and you've probably got "the Perfect Shifting".