Resistance or drag when coasting

[LeoBiker]

Hello everyone,
Just wondered if this is normal or not. I've just recently fitted a front hub motor with PAS only to my Trek hybrid bike. Works ok, but I'm finding after a few steep hill climbs recently that I'm feeling resistance when I stop pedalling and start coasting downhill after using PAS at level five. It's as if although the motor has cut out, it's still engaged and is creating some drag. Also the PAS at level 5 seems a bit jumpy lately, as if it cuts off momentarily and comes back again.
Any help would be greatly appreciated.

 

[vfr400]

It might help if you tell us what motor it is. Anyone want to guess?

 

[LeoBiker]

Hello vfr400. Its a 36v Woosh XF07 250W front hub with 36v17Ah battery/controller kit. No need to guess.

 

[vfr400]

Hello vfr400. Its a 36v Woosh XF07 250W front hub with 36v17Ah battery/controller kit. No need to guess.

OK. Lift the wheel off the ground and turn it by hand in each direction. You should be able to feel the internal gears turning when going backwards, and it should be free when you turn it forwards. If it's the same each way, the clutch is stuck.

Next, give it a spin forwards to see that nothing id binding. it should continue for many turns,

Finally, make sure that the motor connector is in all the way to the marked line, not just in tight.

 

[LeoBiker]

OK. Lift the wheel off the ground and turn it by hand in each direction. You should be able to feel the internal gears turning when going backwards, and it should be free when you turn it forwards. If it's the same each way, the clutch is stuck.

Next, give it a spin forwards to see that nothing id binding. it should continue for many turns,

Finally, make sure that the motor connector is in all the way to the marked line, not just in tight.

Yes I've tried those things already. All seems in order.

 

[vfr400]

There aren't really any other reasons other than it's an illusion. When you have level 5 power on, pedalling is very easy compared with no power - so easy that you think you can freewheel.

Jumpy PAS is normally from either an uneven gap between the sensor and the magnet disc of the magnet disc slipping.

 

[LeoBiker]

There aren't really any other reasons other than it's an illusion. When you have level 5 power on, pedalling is very easy compared with no power - so easy that you think you can freewheel.

Jumpy PAS is normally from either an uneven gap between the sensor and the magnet disc of the magnet disc slipping.

I have a left side sensor. I’ll check that tomorrow. Thanks for your help. Much appreciated.

 

[D C]

If your speed is hovering around 15 to 17 mph when you feel it's jumpy, it may well be the motor cycling between off and on to comply with the legal speed restriction,
Dave.

 

[LeoBiker]

If your speed is hovering around 15 to 17 mph when you feel it's jumpy, it may well be the motor cycling between off and on to comply with the legal speed restriction,
Dave.

Thanks Dave, that makes a lot of sense. I think I’ll de-restrict a few notches to avoid that. Could that cause problems other than legal?
Leo

 

[vfr400]

Thanks Dave, that makes a lot of sense. I think I’ll de-restrict a few notches to avoid that. Could that cause problems other than legal?
Leo

The faster a motor goes, the better it is for it. Slow speed at full power is what kills motors and controllers.

 

[LeoBiker]

Noted - thank you.

 

[D C]

Thanks Dave, that makes a lot of sense. I think I’ll de-restrict a few notches to avoid that. Could that cause problems other than legal?
Leo

Never did with my XF07 (which I don't have any more having given to a friend) but you may shorten the range slightly.
Dave.

 

[LeoBiker]

Never did with my XF07 (which I don't have any more having given to a friend) but you may shorten the range slightly.
Dave.

Yes the range is a consideration. Although it’s impressive at the moment even using level 5 most of the time - I can get 40 km and still seem to have half battery level. Is it ok to leave these batteries charging overnight? Views seem to vary on this.
Leo

 

[LeoBiker]

Never did with my XF07 (which I don't have any more having given to a friend) but you may shorten the range slightly.
Dave.

Hello Dave - regarding the XF07 - even derestricted to 40kph, my actual top speed seems to max out at about 29kph when tested on a bike stand. Does that seem a bit slow?

 

[vfr400]

Hello Dave - regarding the XF07 - even derestricted to 40kph, my actual top speed seems to max out at about 29kph when tested on a bike stand. Does that seem a bit slow?

Speed for any motor is directly proportional to your battery voltage. What was it during that test?

 

[LeoBiker]

Speed for any motor is directly proportional to your battery voltage. What was it during that test?

Didn’t check voltage but it’s a fully charged 36v 17ah.

 

[D C]

Hello Dave - regarding the XF07 - even derestricted to 40kph, my actual top speed seems to max out at about 29kph when tested on a bike stand. Does that seem a bit slow?

I got about 33kph derestricted with 36 volt battery.
My motor was bought around 7 years back so maybe more recent ones are slightly different.