Cadence magnet help please

jojocatgirl

Just Joined
Mar 24, 2025
2
0
Hi there, I am really hoping someone can help me! I have had a Freego electric bike for 7 years, it's my daily main transport, so well used. Recently over the last year, it's working fine, then suddenly stops working. The first time this happened and after watching lots of videos, wires checked for connections, all good, I know that my sensor works, red light flashes when pedals move. I cleaned the magnetic plate, as recommended. But I noticed the magnetic plate is warped. If I adjust the distance to the sensor, sometimes it will start to work again. And be fine for a month or so, then the motor stops again. This remedy has worked several times. But this time this remedy is not working. Could the problem be the warped magnetic plate??, I cannot find any answers on this anywhere! I hope someone has some advice, I would be very grateful! I need my bike!!!
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
21,244
8,701
61
West Sx RH
The magnet disc needs to be approx. 1mm gap to the sensor head so if your disc is warped then yes one will see operation issues.
Often the magnet disc is held in place on the bottom bracket axle by small plastic splines incorporated in the disc. Check the disc is firm on the BB axle , that it can't be moved around it's axis by hand .
If it is slipping rotationally one can wrap some eletrical tape around the axle then slide the disc over the tape to try and secure it, alternatively simply buy a new magnet disc.
Most come with a new sensor head as well as a pair, cost about £10 on ebay.
 
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thelarkbox

Esteemed Pedelecer
Aug 23, 2023
1,430
445
oxon
Yes a warped magnet plate could cause issues as the controller looks for a pattern of pulses to confirm pas activation and if warped disrupting the expected impulse pattern it could cause problems.

ebay/ali express a replacement sensor if you buy the same style you need only replace the magnet disk ;)
 
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saneagle

Esteemed Pedelecer
Oct 10, 2010
7,763
3,587
Telford
If you have the large diameter magnet disc, the one you have is difficult to find, but you can buy one of the large 12 magnet ones and press out every other magnet to make it work as a 6 magnet one. The one I had would only work like that.

As you can only buy the magnet disc with the sensor, you could just get an 8 or 10 magnet one and fit the whole lot if you don't mind pullubg the cranks and removingb the bottom bracket to fit it.
 
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jojocatgirl

Just Joined
Mar 24, 2025
2
0
The magnet disc needs to be approx. 1mm gap to the sensor head so if your disc is warped then yes one will see operation issues.
Often the magnet disc is held in place on the bottom bracket axle by small plastic splines incorporated in the disc. Check the disc is firm on the BB axle , that it can't be moved around it's axis by hand .
If it is slipping rotationally one can wrap some eletrical tape around the axle then slide the disc over the tape to try and secure it, alternatively simply buy a new magnet disc.
Most come with a new sensor head as well as a pair, cost about £10 on ebay.
Thanks so much for your help. Tried the tape today, no job, but a new magnet disc is on order. Thanks again.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
21,244
8,701
61
West Sx RH
Thanks so much for your help. Tried the tape today, no job, but a new magnet disc is on order. Thanks again.
OK worth a try with the tape some times.
Let us know how the new disc works out as we like a successful conclusion to a simple issue.