Interesting Question

[Ballynoes]

Hi, I was thinking about my bike today and how it knows what speed I am doing.

Yup the little magnet on the rear wheel spoke.

So I thought, what if it becomes loose and drops off while bouncing about the hills, will this stop the pedal assist from working, as it won’t know if the wheel is turning or not. And should I carry a spare, as I don’t want to be stuck miles from home with a “dead bike”.

So tonight I removed it and tried it round the driveway. It still gives assistance, but the display says “error” and it does not give a MPH reading, obviously.

As I was unable to get up to the 15mph cut off, has anyone any idea if it will keep assisting as it does not know when I hit 15mph.



Just a thought.



It’s a Cube Race 500.

 

[Deleted member 4366]

No, it'll stop working as soon as you get going. instead, you need either a tuning dongle or you need to fabricate a holder for two magnets fixed to the crank arm, and move the sensor into a position to sense them.

 

[Ballynoes]

Hi d8veh,

thats what I assumed would happen, but it still kicked out power when cycling round the drive, albeit at around 5mph, but still the power was there. The display oviously was at 0 as it couldn't detect the wheel going round.

Might need to test it out at a higher speed when I get a chance.

Any other comments welcome.

 

[Gubbins]

If you are thinking of the dongle route you might consider the blackped. it fits internally, is programmable via a smartphone app to give a cut off at your desired cruising speed, can be turned on and off from your display and can have a turning on code (X x button presses) so the bike can appear to be legal.

 

[Ballynoes]

Hi All,

I wasn't thinking of de-restricting it at all (not yet anyway), as it is still under warranty.

My concern was - if the magnet comes of the spoke due to lots of rough riding, as it is a mountain bike after all, will the system think there is a problem and stop assisting my pedalling. I would hate to be stuck 20 miles up a hill, with no assist, as I can easily carry a spare magnet in my rucksack.

I tend to be way up the hills exploring on the bike and sometimes I can be a long way from home, hence why I like to carry the appropriate spares.

Thanks.

 

[Slyko]

It's just not holding tight

 

[Gubbins]

I have never lost a wheel magnet but on one occasion I suddenly lost power and it was a twig got between the wheel and the forks and had moved it.

 

[Steve A]

Easy, take magnet off and try it.

 

[Ballynoes]

that's the plan Steve A if only work would stop getting in the way..