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Throttle activate brakes !?!

Started by FredoGauvino, June 26, 2024, 05:47:24 AM

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Hello all,
I have a Rad City 2 2019 with roughly 3000km on it, that developped a very weird problem...

When I activate the throttle more than half, The brakes activates ...
It works well up to half throttle, but full brake after that.

I tried to locate any cable damage, but did not found any, maybe it is in the frame.

When I unplug the rear brake, the throttle works again normally.
I tested both brakes and they both function normally individually.

I was first thinking of replacing the throttle, but obviously that will not fix the issue !
Also I was looking for a configuration or controller mode change, but that also is not possible.

Anyone had this problem ?
I am suspecting the main harness but would like advice from you guys...

Thanks in advance.
Fred from Montreal


I lean toward the controller.  There is a small resister inside the controller wrapped in black plastic.  It will be labeled.  Another posted he got an old controller and replaced that part.  There are 2 in there one for front and one for rear brake.   

As long as you apply both brakes, with the rear disconnected, the good brake will disengage the motor. Of course this isn't the safest way but it is a away around your probably at least temporarily. 


Quote from: FredoGauvino on June 26, 2024, 05:47:24 AMWhen I activate the throttle more than half, The brakes activates ...
It works well up to half throttle, but full brake after that.
I'm just guessing but could it be that the cables are tightly zip tied?
Literally is LITERALLY the most annoying word of the decade.


I did some more tests,  8)
When I plug only the rear brake, in any of the 2 rear or front plug, the throttle goes backward. :o
When I plug only the front brake, no problems what so ever. ;D

Therefore there is definitely something wrong with the rear brake! :o

I am guessing that there is a residual small resistance instead of a full contact "short", that fools the controller whenever the throtle is applied.

For now on, I will continue using the bike without the rear brake, as I always use both brakes at the same time.

This winter I replaced the original mechanical brakes with NUTT hydraulic ones, so this is now more messy and complicated than buying a new brake lever.

Thanks for your ideas !


My problem is the brake sensor that is too sensitive.
I was able to order some from AliExpress, hopefully that will solve the issue !