Bosch question

neilob

Finding my (electric) wheels
Dec 8, 2018
5
0
72
Hi all. I have a road/gravel bike fitted with the Bosch Active Line system (250w motor, 500wh PowerTube battery). For riding on private land and trails only I am thinking of moving the speed sensor from the rear wheel to the crank (I fully understand that this is not legal on the road and could invalidate warranty, so please don’t feel inclined to remind me of these things). The consequence of this is that the bike electronics are tricked into thinking that cadence is actually speed and because cadence is a lot lower than rear wheel revolutions it allows the 15.6 mph limit to be exceeded. One inmediate problem is that the speed display is wrong but that can be overcome by using a Garmin. My question however is how would this modification impact the delivery of power and the application of torque? I guess I don’t really understand how the speed is used to derive the level of assistance. Thanks!
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,152
6,316
i doubt it will work but all you will get is a 503 error on the display if it does not but you can buy a dongle.

it is just a speed sensor so cuts out at the speed set in the software so it wont effect anything else.

 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
2,214
562
77
Hi all. I have a road/gravel bike fitted with the Bosch Active Line system (250w motor, 500wh PowerTube battery). For riding on private land and trails only I am thinking of moving the speed sensor from the rear wheel to the crank (I fully understand that this is not legal on the road and could invalidate warranty, so please don’t feel inclined to remind me of these things). The consequence of this is that the bike electronics are tricked into thinking that cadence is actually speed and because cadence is a lot lower than rear wheel revolutions it allows the 15.6 mph limit to be exceeded. One inmediate problem is that the speed display is wrong but that can be overcome by using a Garmin. My question however is how would this modification impact the delivery of power and the application of torque? I guess I don’t really understand how the speed is used to derive the level of assistance. Thanks!
You might be looking for this:-
regards
Andy
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,986
Basildon
Bosch changed their software to detect the speed sensor hack. It worked on the first version, but not since. There is some time involved in the detection, so if you do it and test it, it'll work for a bit, but then you get the error code logged and it won't work until you change it back.
 

neilob

Finding my (electric) wheels
Dec 8, 2018
5
0
72
Thanks vfr400. I wondered about that.....how long is ‘ a bit’? Do any of the dongles work with this version of the Bosch engine?
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,152
6,316
it will work for a few seconds and you will get a 503 speed sensor error on the display and it will cut all power unless you put it back as it was or turn it of and on.

this hack was for the gen 1 motors and was removed for the gen 2 motors tho some could get it to work on some firmware versions at the start of gen 2 but long gone now.

dongles will work best option is the badass ones as can be easily removed but it wont work if the magnet is on the disc rotor.


 

neilob

Finding my (electric) wheels
Dec 8, 2018
5
0
72
I'm taking a lot of your time but believe me it is really important to get this fixed! I tried it last week and it worked for 30+ miles. No error codes. I just sensed that it wasn't quite the same as when it was in the normal configuration hence my original post asking if speed was an input to the power assisted and torque calculation.
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,152
6,316
you might get a few more mph but it wont be anything like a dongle i did get a couple more mph buy changing the wheel size but not a option on new displays as only dealers can change this now.


with a dongle and the gearing i can hit over 30mph ;)
 

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