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BBSHD significant resistance when pedaling with motor off or not engaged

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    BBSHD significant resistance when pedaling with motor off or not engaged

    Hello,

    I have been riding my BBSHD for several weeks now and have noticed that there is now quite a bit of resistance when I pedal when the motor is off or when not engaged. I believe when I first got it installed there was pretty much no resistance when pedaling only (felt the same as a peasant bike ;) but just slightly heavier) but now there is some resistance.. the motor has about 400 miles on it so far. I don't remember a specific moment when this started, so no bad noises and the motor seems to be working fine otherwise. I purchased the motor and Shark 52v battery from Luna.

    When coasting there is no resistance at all but when i start to pedal with the motor off or at PAS 0, i begin to feel resistance and have a hard time going very fast. If I get up to speed by pedaling hard and then stop pedaling, i can feel a slight "release" when i start coasting, as if the motor is disengaging once i stop pedaling and allowing the bike to coast freely. I believe there's a very faint whirring noise when pedaling as well. I assume this resistance and faint noise is due to me cranking the motor. From what i have read on the internet it sounds like the motor should be disengaging completely when only pedaling but mine doesn't seem to be doing that. another poster in a different e bike forum sounded like he had the same problem but came back a while later and said the problem just went away one day. Any ideas? Is there a setting that needs to be adjusted or maybe some way to reset the system? I have the 750c dispay and programming cable if needed. Let me know if you need any more details.

    #2
    If you lift the rear wheel and rotate the cranks by hand, do you feel unusual resistance? Does resistance happen only when the kit is "on" or both on or off? If it is a freewheel (clutch) issue, you should feel it this way. Could be some bb bearing issue too, but I have no idea really. Subscribing to the thread so I can learn :)

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      #3
      I feel a slight resistance when the motor is off, and no resistance when set to 0 pass. I have a couple of ebikes and notice this on all of them since new.

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        #4
        Feewheel/clutch might be hanging up? It should always pedal with little noticeable resistance.

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          #5
          i feel the same resistance when motor is off with battery hooked up, off with no battery and on at PAS 0. there is still resistance when cranking by hand as well. If it is a freewheel/clutch issue, what's the fix for that?

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            #6
            Mine has resistance the same - battery on or off and PAS 0 there is noticeable resistance turning the cranks by hand. Feels like stiff gears or bearings. It is a fairly smooth mechanical resistance, not the strong and very jumpy electromagnetic resistance you feel if you try to roll the bike backwards. I'll revisit after I put some miles on my bike - right now it is brand new, just installed and test-connected everything, so I have not ridden it.

            I can'tell feel a difference with battery off or bike on and PAS 0.

            The resistance is not huge, but it is not free-turning either. Backpedaling is easier vs. no load pedaling forward. So, I think the added resistance is due to the gears working (see next two posts, the rotor should not be turning when pedaling forward with the bike on or off and PAS-0 or with the bike off.
            This is on a brand new BBSHD, stock programming (Bafang's stock settings for the full power version)
            Last edited by Kocho; 06-20-2017, 01:31 PM.

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              #7
              Ok, I've been doing some more research and learning how these things work and I think I may have narrowed the issue down to the nylon gear. There’s a forum post by Sebz on here regarding taking apart the whole thing and greasing everything. In the Section where he takes out the nylon gear he makes a comment saying “the nylon gear has a one way bearing that acts like a clutch so it needs to bite on the shaft (of the pinion gear), adding grease on the shaft could result in slipping.” So is this the point that should be disconnecting the cranks from the motor when under pedal power? If pedaling, is that one-way bearing supposed to allow the pinion gear axle to turn freely without spinning the nylon gear so no energy is transferred to the motor? When under motor power, the nylon gear spins, that one way bearing locks in on the shaft, spinning the pinion and large gear and therefore propelling the bike forward? Hopefully I’m thinking about that right.

              This is how I understand it works, said another way: Pedaling turns the axle which has gear teeth on it that the clutch locks into. Clutch locks into the inner teeth of the large gear and turns it, which turns the pinion gear, which sits inside the nylon gear. At this point, under pedal power alone, the pinion gear should spin freely inside the nylon gear and the nylon gear should remain stationary, correct? If for some reason the pinion gear isn’t spinning freely and the nylon gear is also turning, that would essentially result in cranking the rotor within the stator (hopefully those are the correct terms), causing increased pedal resistance?

              So could my issue be that the one way bearing locked up on me so when i'm pedaling i'm cranking against the whole motor?

              Comment


                #8
                I just watched this video, which disassembles the BBSHD and BBS02. Skip to minute 22 or so for the part where he takes out the nylon grear and mentions the one-way bearing:

                https://youtu.be/E46OW4ubK84

                It seems that this bearing should allow pedaling forward without turning the rotor of the motor. However, I think the pedals are still turning the planetary gears and [not] the nylon bearing, and given that they are pretty well greased in thick grease, it seems there will be some increased resistance vs. turning the pedals backwards when the clutch will disconnect the pedals from the gears and on my bike there is virtually no resistance backpedalling. If you do roll the bike backwards, then the one-way clutch in the nylon gear will engage and rotate the rotor on the motor and you will feel it differently (you will feel the magnetic resistance of the motor).

                The forward pedaling resistance on mine is small, it is hard to quantify, but lifting the bike off the ground and placing medium sized pliers on the pedal is enough to start the rotation. So I would estimate it takes about 8oz (250g) weight to overcome the resistance. Half a 16 oz bottle of water placed on the pedal will overcome the resistance on mine...

                Is yours stiffer? And the forward rotation resistance is fairly smooth, unlike rolling the bike back where you feel the rotor skip between the positions of the magnets and resisting you.
                Last edited by Kocho; 06-21-2017, 10:59 AM.

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                  #9
                  If that one way bearing is working, it should not matter if the bike is on or off - the motor is not turning either way, so the resistance should be the same. Are you sure yours are not the same too? Since the motor is not turning nor is it helping, it should not matter if the bike is on or off.

                  Originally posted by Harold View Post
                  I feel a slight resistance when the motor is off, and no resistance when set to 0 pass. I have a couple of ebikes and notice this on all of them since new.

                  Comment


                    #10
                    Hey guys,

                    When you pedal without the motor running (either in PAS 0, LCD off or battery off) the following parts move:
                    • Crank arms: obvious
                    • Secondary gear: Clutch bites on the secondary gear so it will spin too.
                    • Pinion gear: is engaged by the secondary gear.
                    Nylon gear does not spin! There is a one way bearing in the nylon gear for that. There are no electronics that can change this behaviour.. it's 100% mechanical.

                    However when you reverse the the bike, all the motor parts move, nylon gear and rotor! That is why it's so hard and jerky.



                    Also back pedalling is super easy because only the arms move, the clutch is disengaged. So rotating the cranks forward will be harder as you have a few part to move (chain, wheel, secondary gear and pinion gear)

                    But that being said, if you remove the chain and spin the cranks forward with your hands it should be really easy.. very little resistance... can do it with my pinky!

                    hope that helps.
                    Last edited by Sebz; 06-21-2017, 09:48 AM.

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                      #11
                      Oh, my bad. Looking at the video again, it shows that quite clearly. I suppose there is some friction in that bearing too.



                      Originally posted by Sebz View Post
                      Hey guys,

                      When you pedal without the motor running (either in PAS 0, LCD off or battery off) the following parts move:
                      • Crank arms: obvious
                      • Secondary gear: Clutch bites on the secondary gear so it will spin too.
                      • Pinion gear: is engaged by the secondary gear.
                      Nylon gear does not spin! There is a one way bearing in the nylon gear for that. There are no electronics that can change this behaviour.. it's 100% mechanical.

                      Comment


                        #12
                        Hi,
                        Regarding to all the messages here I made a video of how it works in my case.
                        I also suffer from hard pedalling without the motor on.
                        In my case the Nylon Gear is working all the time, in both sides.
                        Is there a problem with bearings in Nylon Gear?
                        While coming back home I had to ride without motor and it was so hard and annoying, especially going up the hill.
                        I do not remember how it was working as a new model but I think it was not so hard as now.
                        Of course with energy it is working all fine.
                        Hope somebody could help.
                        Greetings
                         

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                          #13
                          I am experiencing the same problem. Pretty strong resistance when only paddeling or when in in PAS 0. very ennoying and want to fix it...

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                            #14
                            Curious whether anything was ever figured out for those experiencing this? I outrode my battery yesterday and experienced the same thing for my last 5 miles or so. Very difficult pedaling...had to hobble home on the 40T gear most of the ways...the smaller gears were too difficult to pedal in. I turned the battery off (has a toggler power off/on switch) and it made no difference. I did not physically remove the battery (shark style on frame mount) however.

                            I have about 300 miles on my BBSHD and with battery power it has worked flawlessly. I've only been riding it with at least PAS 1 or 2, so hard to tell if this just developed recently or not. But I rode this bike hundreds of miles before the BBSHD conversion, so I know what it should feel like...this was significantly more drag/resistance...
                            Last edited by ColinC; 03-02-2020, 07:20 AM.
                            2017 Growler 26" fat bike BBSHD

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                              #15
                              Looks like this thread has gone dormant for awhile but I am experiencing the same thing and wondering if there was ever a resolution. Just installed a BBSHD and have resistance to pedaling when either OFF or PAS 0. It takes ~ 1 1/2 pounds of force on the pedal to start the crank arm rotating and this is after the rear wheel is spinning so all the resistance seems to be from the motor itself. Never felt anything like this before the BBSHD install on this bike. About to start taking things apart to see if I can find further clues but wanted to see if anyone else has already been down this road.

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