Gear Sensor

The rivet nuts from China still haven’t arrived delaying my bike modifications, until I realised I could fit the gear sensor.  This is an optional component which I’d previously decided to fit.

The purpose of the sensor is to detect when a gear change is going to occur and momentarily stop power to the motor.  This is supposed to reduce wear and damage to the chain and gears.

The way it works is by detecting movement in the cable (wire) that connects the gear change lever on the handlebar to the rear derailleur.  You may recall I’ve already removed the front derailleur.  Inside the sensor the gear cable passes over a small pulley wheel which rotates when the gear level is pulled.  The puller is connected to an electronic sensor which sends a signal to the motor management system.  The management system then briefly cuts power to the motor.

My method was to disconnect the cable at the derailleur and pull it free of the tube in which it is encased at the handlebar end.  However before I could do that I needed to remove the ferule crimped to the derailleur end which stops the end of the wire from fraying.

 

There were two potential hazards.  If the wire wasn’t cut cleanly then it might prove hard to push the wire  back through the tube during the latter part of the process.  Moreover the cable might fray during the operation creating more of an issue.   My solution was to put a small amount of superglue on the last 10mm of the wire immediately before the ferule. Rather than use my electrical pliers or side cutting pliers to cut the cable, I purchased a cheap guillotine style pliers in an effort to get a clean cut.

 

To my pleasure and surprise my method worked.

With the wire extracted from the tube I was able to fit the sensor onto it.  I also had to use my new pliers to cut the equivalent length of the sensor off the tube.  This was to ensure there was sufficient wire at the derailleur end.

At the derailleur end I needed to do the connections and adjust the derailleur, before crimping a new ferule onto the wire.

Job done