Carrera crank change

[Reddave101]

Hi all hoping someone may know before I start stripping and changing. I’ve recently bought a carrera crossfire e-bike. The crank sensor cable has snapped so needs replacement as getting error 21. I’ve looked at the crank and the part that swings freely(holds the sensor) is jammed to the crank itself which explains how it snapped the cable. Personally I think it’s a bad design for this reason. The question is could I put a normal crank on with a standard pos sensor? Has anyone done this? It’s the older 3 wire sensor on it and the pos is also 3 wire but would need to change the connector to the controller, don’t want to start cutting and stripping, soldering if wasting my time?

thanks for any help

 

[saneagle]

Hi all hoping someone may know before I start stripping and changing. I’ve recently bought a carrera crossfire e-bike. The crank sensor cable has snapped so needs replacement as getting error 21. I’ve looked at the crank and the part that swings freely(holds the sensor) is jammed to the crank itself which explains how it snapped the cable. Personally I think it’s a bad design for this reason. The question is could I put a normal crank on with a standard pos sensor? Has anyone done this? It’s the older 3 wire sensor on it and the pos is also 3 wire but would need to change the connector to the controller, don’t want to start cutting and stripping, soldering if wasting my time?

thanks for any help

The sensor is screwed to a stationary part of the chainwheel. There are two lugs on the sensor that fit either side of a fixed stop to prevent that part of the chainwheel from turning.

The crank mechanism is extremely wafty. The fixed and moving parts of the chainwheel are separated by a thin dust seal. If you get the crank covered in mud or grime, then don't use it for a bit, the two parts become glued together, so when you turn the crank the fixed part moves wiyh it and one lug breaks and the sensor, letting it go round with the crank.

Also, if the chain comes off, it can cut the wire.

If you take it all apart, clean it, epoxy on a new lug and solder the wires, it should work again, but you need to add servicing it to your maintenance schedule. If that seal is damaged (very likely), I doubt that you'll find a replacement, so you'd have to clean out the inside often.

You cannot fit a normal pedal sensor without replacing the controller, and there can be some compatibility issues with that. If it were my bike, I'd try and keep the torque sensor working until the battery expired, then I 'd replace all the electric parts except the motor.

The later models have some changes in the area of the torque sensor, but I haven't had a chance to study them yet. They're very expensive as spare parts if you can get them. Powerbike used to sell them, but they've disappeared now.

Incidentally,if you take one of the springs out, you get max power more easily - 20% less effort.

Here's the one I disassembled so that you can see what's inside.

Carrera Crossfire/Vulcan Torque sensor

I recently stripped one down so i can describe how it works. To disassemble it, you take the crank/chainwheel off, then remove the 4 screws in the back. There's 4 shim washers in there, so be careful not to lose any. The sensor is held on with three small screws. The sensor is partly...

www.pedelecs.co.uk

Just seen this. Carrera owners get one while you can. Note the 560 sold an 3 left:

SR SUNTOUR HESC Chain Set ATS Torque Sensor - Carrera Vendetta Vengeance Vulcan | eBay

New SUNTOUR Manufacturer Original.

www.ebay.co.uk

 

[Reddave101]

Thanks for the reply. The torque sensor is completely destroyed with no hope of revival. In my logic I was hoping that replacing the crank and using a normal pos sensor kit and changing the plug to fit the controller it would in theory work the same way. Would measure the revolutions of the crank and engage the motor. I’ve never seen or used this kind of carrera sensor before so not sure how it works, magnets like the pos or light(not sure as look like little bulbs). My carrera sensor is using 3 wires and a pos uses 3 wires so that was my theory, thanks again

 

[saneagle]

Thanks for the reply. The torque sensor is completely destroyed with no hope of revival. In my logic I was hoping that replacing the crank and using a normal pos sensor kit and changing the plug to fit the controller it would in theory work the same way. Would measure the revolutions of the crank and engage the motor. I’ve never seen or used this kind of carrera sensor before so not sure how it works, magnets like the pos or light(not sure as look like little bulbs). My carrera sensor is using 3 wires and a pos uses 3 wires so that was my theory, thanks again

Great idea, but it won't because it gives the wrong type of signal. The torque sensor has four wires to tell the controller the speed of crank rotation via a high frequency pulsed signal and a displacement (torque) via a 0 to 5v analogue signal. A pAS sensor gives a relatively low frequency pulsed signal only. You'd need a new controller too, but then the battery might not work, depending on which version you have.