Sensor mount damaged; what happens with no sensor?

Paul Wrighton

Pedelecer
Aug 6, 2018
84
24
64
I just completed a brake bleed on my rear brake (happy to say successfully) and when replacing the wheel I must have knocked the sensor somehow. The first I knew of any damage was when I spotted a piece of broken plastic on the ground and traced it back to the mounting that held the sensor in place for picking up the wheel revs.

On closer inspection the plastic was very very crumbly and must have been near end of life. I shall see about my LBS sourcing a replacement in the longer term, but for the short term I have just fashioned a loop of insulating tape to do the job. On a test ride all was well and my speed reported and motor operation all normal.

But it got me to wondering... what if that sensor were to come adrift on a ride, how would it affect my bike? I am guessing there are many people on this forum that have the answer, and my guess is that without a sensor I would lose all assistance and revert to a non-Ebike riding experience.


Could anyone confirm my guess?
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,786
The European Union
I just completed a brake bleed on my rear brake (happy to say successfully) and when replacing the wheel I must have knocked the sensor somehow. The first I knew of any damage was when I spotted a piece of broken plastic on the ground and traced it back to the mounting that held the sensor in place for picking up the wheel revs.

On closer inspection the plastic was very very crumbly and must have been near end of life. I shall see about my LBS sourcing a replacement in the longer term, but for the short term I have just fashioned a loop of insulating tape to do the job. On a test ride all was well and my speed reported and motor operation all normal.

But it got me to wondering... what if that sensor were to come adrift on a ride, how would it affect my bike? I am guessing there are many people on this forum that have the answer, and my guess is that without a sensor I would lose all assistance and revert to a non-Ebike riding experience.


Could anyone confirm my guess?
With a KT controller on the GSM the motor doesn't cut out. A speed is indicated but it has nothing to do with real speed.

From personal experience.
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,786
The European Union
You know you can use a wheel speed sensor instead of the motor for the speed signal?
Yep have one mounted. When I first got the GSM I didn't have a working sensor for about 700 km or so.
 

Paul Wrighton

Pedelecer
Aug 6, 2018
84
24
64
Per my signature it's a KTM macina 29 and the motors a Bosch gen.1 (metropole). It's the wheel sensor on the frame that's held on by tape now.

Thanks for the info
 

Advertisers