Motor seems to be 'hunting'

[alan_sh]

Riding along after a steepish hill and the motor doesn't seem to be giving me the push I am expecting. When I stop pedalling, I can feel it slowing me down. When I pedal, I can feel it work, not work, work, not work. But then sometimes it works fine.

I am not sure how to better describe it.

Plenty of power left in the battery.

Anyone any ideas whats going on? The bike is new - only done around 50 miles in total.

Alan

 

[steve_sordy]

Is your bike speed at the time this is happening at around the cut off speed? (You did say after a steepish hill).

Irrespective of speed, if the bike is doing fine and you are in a big gear, then often the motor will not provide any assist because it doesn't need to do so to stay at that speed. Then a slight incline and in it comes, then the slight decline and out it goes.......

 

[alan_sh]

I was doing around 10-12 mph at the time, so I don't think I was at the cutoff speed (I have no idea how to find what that is - but I have been faster and felt the assistance). The steep hill also wasn't as easy as I was expecting.

This only seems to have started in the last 2 rides. My first rides (20 miles with pleasant gradients, 10 miles with a big hill) worked really well.

Could be time for a visit to Decathlon to see what they say - when I'm back off my hols next week.

Alan

 

[stiv674]

Is it in all assist modes? Most seem to be less smooth in Turbo or Boost mode in my experience, unless you're putting in a lot of effort yourself.

 

[alan_sh]

Could be - it was in the top (number 3 mode) going up the hill.

 

[Jackware]

Too much assist for the torque you're applying or the gear you're in . I've experienced it on my Haibike PW-X - either drop to a lower assist level or shift to a higher gear.

#edited for clarity

 

[alan_sh]

Thank you - I'll try that tomorrow.

 

[All4Fun]

Check the speed sensor too, my wife's bike had also issues, Bosch CX, the gap was more on the max of the specs, now it is on the minimum and no problems anymore.

De groet'n...

 

[jerry]

Have the same - or related issue - of the support fluctuating. Of course, in EMTB, it's supposed to fluctuate; but such support changes can also be found on lower settings (eco,...). On occasion, even Eco gives me a turbo-like surge every now and then, just for a second or so, and always when changing the power applied to the pedals. I expect it has to do with the torque sensor, not the speed sensor.
But, as it's rare and not intrusive, I've not had it checked out by dealer.

 

[alan_sh]

Thanks both - I am off for a ride today and will check it out.

 

[alan_sh]

Did a 16 mile ride and it behaved itself. But no steep hills. I then slipped a disk (I think) lifting the bike onto the rack. So, no ride today (or possible for a while - depending on the pain killers).

 

[steve_sordy]

Deffo not a slipped disk, you would be not writing the email if it was. Probably a muscle spasm. They are bad enough and feel awful, but nowhere near as bad as a slipped disc. Pray you never get one.

If you have intermittent back problems, or even better if this was your first, then get to a Pilates class and strengthen your core muscles (abs and lower back). Pilates is also great for mtb, as in addition to improving your core it improves balance, flexibility and strength.