Cube Reaction 500 - where is the speed sensor!

[rogerroger]

Am loving new(ish) CUbe Reaction 500 and done about 1,200 miles on it. All going fine but the other day kept getting speed sensor errors. The speed's all over the place to the motor keeps cutting out. Really annoying, but I've read the sensors can just get dislodged. The only thing I've done is add a rear rack so maybe I knocked something.

But I can't find the sensor. All web searches show a little plastic dongle thing on the chain stay but I don't have one. Is it built into the crank hub? Is it this hole / port hightlighted in the photo ? or could it be under this plastic cover cable tied to the chainstay?

Thanks

 

[cozzy]

You have a rim magnet, so it's likely in the motor assuming Bosch. Pita to derestrict.

 

[rogerroger]

You have a rim magnet, so it's likely in the motor assuming Bosch. Pita to derestrict.

Thanks. No interest in de-restricting though, just want it to work!

 

[Mikerb]

your rack may be blocking the ability of the speed sensor in the motor housing to pick up the magnetic field from the rim magnet ( the rim magnet is the rectangular block attached to the tyre valve in your photo). I suggest you remove the rack and see if that fixes your problem.

 

[rogerroger]

your rack may be blocking the ability of the speed sensor in the motor housing to pick up the magnetic field from the rim magnet ( the rim magnet is the rectangular block attached to the tyre valve in your photo). I suggest you remove the rack and see if that fixes your problem.

Thanks. The first thing I did was to remove the rack but I still have the problem. It just seems too much of a coincidence that the bike has been trouble free for ten months but I get this sensor issue the first ride after installing a rack.

I just want to locate the sensor so I can inspect it but I don't know where it is. There's nothing in the user manual and nothing online concur with my bike.

 

[Mikerb]

The sensor is in the motor...you cannot access it. The obstruction of the rim magnet by the rack may have created a fault code that needs to be cleared ....or...it may have damaged the magnet.
Is your bike Bosch Smart System or the previous generation with the Purion controller? If it is the former the Flow App should enable clearing the fault code. If the latter you will need to get a Bosch dealer to do that.
Replacing the rim magnet may be worth a try first.

 

[rogerroger]

The sensor is in the motor...you cannot access it. The obstruction of the rim magnet by the rack may have created a fault code that needs to be cleared ....or...it may have damaged the magnet.
Is your bike Bosch Smart System or the previous generation with the Purion controller? If it is the former the Flow App should enable clearing the fault code. If the latter you will need to get a Bosch dealer to do that.
Replacing the rim magnet may be worth a try first.

Thanks, that makes sense about the sensor and explains why I can't find it. I can't possibly see how a rack could interfere with it though as it's nowhere near the magnet.

Bike was supposed to have the Purion display but the shop didn't include it and didn't care when I complained. It just has the LED controller. The error showed in the Flow app but there was no explicit option to clear it, it has now just disappeared after it's been turned on and off a few times.

There was loads of dirt under the bottom cover which I have now cleared out. It's still giving erratic speed readings but doesn't seem to generate the error on the controller and app. All very confusing.

It is under warranty but I don't really want to deal with the shop who sold it as they are useless and have no idea of customer service.

 

[rogerroger]

The only thing I can find online.

 

[Mikerb]

OK so its a Bosch Smart System equipped bike. You can clear fault warnings by pressing the square button on the LED Remote. If the fault has now gone and you have removed the rack, it does look like that caused the fault report. Also be aware that any magnetic field in the area of the rear wheel can interfere with the sensor as well as excessive dirt or debris on the magnet.

 

[rogerroger]

I'm still getting the problem with the rack removed. The rack is aluminium so really don't see how that could possibly interfere. There was quite a bit of dirt between the magnet and the rim so hopefully that's the issue - I've not tested it yet.

 

[rogerroger]

*** update ***

Well having cleaned everything and charging the LED controller (which I didn't even know you had to do) I still had the problem, so took it to local eBike shop. They said the rim magnet wasn't tight enough and that they'd now done it which had fixed the problem. I told them they were having a laugh, but was completely prepared to accept this if it worked, which they insisted it would. But, 300 yards out of the shop it plays up again so back I go.

They've been in touch with Bosch and apparently it's a dodgy sensor, but, as this model is built into the motor, the whole motor is going to have to be replaced. At Bosch's expense under warranty, so that seems a costly design decision by them.

I'm still going to be out of pocket on a 10 month old bike though as still have to pay the bike shop's labour. Cube have flatly refused to pick up the bill, even the bike's under warranty.

 

[Mikerb]

they did not try a new rim magnet??

 

[rogerroger]

they did not try a new rim magnet??

Don't think so - they've been in touch with Bosch so I guess they'd have suggested that...