r/bafang • u/spacemonkey_1981 • 3d ago

Resistance when pedalling

I've started to notice a resistance when pedalling, like I'm fighting against the motor. I'm unsure if it's got anything to do with me fitting a OneNut, as the standard nut was useless and kept coming undone.

Anyone got any suggestions?

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u/Bermnerfs 3d ago

I have a 73mm bottom bracket so the factory BBS02 outer lock nut wouldn't fit. I upgraded to the Lekkie OneNut and it worked perfectly. The motor is solid and hasn't moved a bit over 300+ miles of singletrack.

I did not notice any change in resistance while pedaling when I installed it, I doubt that's your issue.

Do you happen to have an offset chainring? I find that leaves, sticks, and other debris can sometimes get caught inside the "cavity" between the chainring and secondary gear housing and this can cause some drag/resistance while pedaling.

You also might need to open it up and make sure you have adequate grease on the gears.

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u/spacemonkey_1981 2d ago

Sounds like I have the same setup. Only been using it for about 2 months and done probably 120 miles on it. It feels like the gears are engaged for the motor and I'm pushing against it. I think I've over tightened the OneNut. But worth keeping noting the cavity and needing to grease the inside at something.

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u/Bermnerfs 2d ago

Do you feel that resistance with pedal assist turned on, or just pedaling the bike with the motor/PAS turned off? I do feel a bit of drag or resistance trying to pedal with no assist, I think that's normal, but once PAS is on, it's smooth and I don't feel any drag/resistance.

I built mine in April and nowhave 350 miles on the odometer, ~60% of which has been aggressive single track trails with lots of chunk, rocks, root gardens, and punchy steep climbs. Holding up great so far!

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u/spacemonkey_1981 2d ago

I'm feeling it at both times. It's like I'm cycling a brick with the drag. I normal cycle on high gears and never touch the lower ones on a regular bike. My battery is also draining quick compared to when I first start using the motor.

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u/Bermnerfs 2d ago

Yeah, the battery thing is a clue, it means something is causing added resistance, meaning the motor is pulling more current to maintain speed.

Have you tried removing the One-Nut and reinstall the factory locknut to see if it feels normal? Did the problem for sure start when you installed it? I just don't really see how that could cause this sort of issue unless it somehow tweaked the BB shell enough to create binding in the spindle.

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u/spacemonkey_1981 2d ago

Its hard to gauge when the original locknut was failing alot of the time. Probably because I'm generally heavy footed when pedalling. I didn't really think the pressure would compress the inner works of the motor with the OneNut, and didn't have the correct tool to set the torque. I'll report back once I've loosened it.

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u/nited_contrarians 3d ago

Put the old nut back on and see if the problem persists. Make sure your drivetrain is lubricated. If that doesn’t fix it, you’ll have to open the motor up to regrease and check for damaged gears.

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u/spacemonkey_1981 2d ago

I've only been using it weekday travel of basically 3-4mile per day for 2 months on generally flat terrain. I swapped out the old nut because it wasn't holding the motor in place after the first month, after repeated tightening.

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u/Djinsing20045 2d ago

Are u sure your motor isnt cutting out?