Bosch motor probs??

[Richiefromboston]

So Ive been railing my trek through lynn woods in ma. and its wet in there, just so you know. Not submerging or anything, just saying so you have the info. I decided to swap the factory Bontrgaer rear wheel with 12 speed XTR casette back on (taking Race Face carbon wheel with 12 speed XTR casette off) Because I believe the bontrgaer has better engagement (looking to buy Bontrager crabon wheels) When I did this I forgot to reattach the speed sensor onto the disc, when I got to the woods the bike coded, and would only give power at intial startup then nothing. Took it home installed sensor went back to woods today and the bike felt like I had no motor , no code or anything ,speedo worked. But it was super hard to try and pedal and the chain snapped. WTF, took it home installed brand new chain and it threw the chain. ANYONE run into similar situation, at all?? lemme know. Thanks

 

[Jerma]

What I have _heard_ is that the Bosch motor has a system to detect it you are trying to fiddle with the speed limit. I am now assuming, that as the speed sensor did not provide any data, the motor controller thought of such fiddling being done.

When the motor detects this, it goes into limp mode. Meaning it will turn on normally, but will not give you any assist. To get this reset, you need to pedal (or some other way) for about 10-15km (so i'v heard) and then turn off and back on the system and it should work again normally. Some people even use a power drill to turn the cranks to get the needed distance to reset the error on the motor.

I think easiest is to go to your local Bosch bike dealer/repair shop to get it connected to the service software for trouble code readout and reset of the system.

 

[Yoak]

Hmm, I've swapped wheels with my normal bike and forgot that I didn't have a speed sensor on. It threw a code, but I only had to turn it of and on, attach the original wheel and everything was back to normal

 

[Richiefromboston]

What I have _heard_ is that the Bosch motor has a system to detect it you are trying to fiddle with the speed limit. I am now assuming, that as the speed sensor did not provide any data, the motor controller thought of such fiddling being done.

When the motor detects this, it goes into limp mode. Meaning it will turn on normally, but will not give you any assist. To get this reset, you need to pedal (or some other way) for about 10-15km (so i'v heard) and then turn off and back on the system and it should work again normally. Some people even use a power drill to turn the cranks to get the needed distance to reset the error on the motor.

I think easiest is to go to your local Bosch bike dealer/repair shop to get it connected to the service software for trouble code readout and reset of the system.

IF its in "limp mode" does display work as normal?

 

[Mikerb]

IF its in "limp mode" does display work as normal?

I think you need to separate any rear wheel issue from a motor issue. Even if the motor is giving no assistance there is no reason why it should break a chain or be that difficult to pedal if in a low enough gear. So you need to check the rear wheel you have fitted to see if it operates normally on a workstand in terms of axle rotating freely and freehub operating properly.
When you refitted the magnet to the rotor on the wheel you changed to, you had no motor errors and the speedo worked. It can only recoord speed based on reading rear wheel rotation via the magnet and sensor, so that suggests to me the rear wheel could well be your problem rather than the motor.

 

[Richiefromboston]

I think you need to separate any rear wheel issue from a motor issue. Even if the motor is giving no assistance there is no reason why it should break a chain or be that difficult to pedal if in a low enough gear. So you need to check the rear wheel you have fitted to see if it operates normally on a workstand in terms of axle rotating freely and freehub operating properly.
When you refitted the magnet to the rotor on the wheel you changed to, you had no motor errors and the speedo worked. It can only recoord speed based on reading rear wheel rotation via the magnet and sensor, so that suggests to me the rear wheel could well be your problem rather than the motor.

put new chain on, same wheel as original experiment and changed the chainring( got dinged up when chain broke) put bike on stand hand cranked out 10 miles and shes up and running again all is good. going to woods tonight for serious shakedown run. The reason I installed the stock alloy bontragers rear wheel back on (instead of race face carbon) was The engament on bontrager was better than race face with the Vault hubs, I wanted to verify that it was the rim and not my imagination. I may be buying the bontrager carbon wheels if that is indeed the case.

 

[Richiefromboston]

took it out on the trail for 20 miles not a problem, all is well. must have gone into limp mode and I broke the chain trying to pedal against it.

 

[Bearing Man]

took it out on the trail for 20 miles not a problem, all is well. must have gone into limp mode and I broke the chain trying to pedal against it.

Just out of interest, how many miles had the old chain done?

 

[Richiefromboston]

Just out of interest, how many miles had the old chain done?

440miles