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BBSHD "Snapped" Rotor with Bearing??

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    BBSHD "Snapped" Rotor with Bearing??

    With the temps at 60deg today(IN FEB!) I decided to take the bike out for a ride. With no warning i lost all power and the motor started making a terrible grinding sound. I could tell the motor was in trouble, so i stopped then and there. I figured i had "peanut buttered" the nylon gear and that was the noise. So I shut off all power and pedaled home(not fun). Once home, I pulled the BBSHD off the bike and carefully followed the steps listed on "how to replace nylon gear"......which was linked from Lunas site.(Thank u Luna. That made it very easy). But once apart, it was easy to see my problem is NOT the nylon gear. Mine looks pristine. Even the Lubrication looked clean and good. But I DID notice that mine was TOO easy to disassemble. The step of removing the outer case on the non controller side was supposed to be kinda hard to get off. Mine almost fell off once the bolts were removed. So here are some pics of the internals and what I ASSUME is bad. It looks as if I snapped the Rotor Bearing shaft where the spiral gears meat the rotor itself. I did not see anything on Lunas site for replacement parts. So heres what i really need:
    1- Confirmation that the part in the picture is def broken and not supposed to be like that(dont know how)
    2- Where to get said part
    3- Any recommendations on what I should do when doing the repair.....ie: go ahead and replace nylon gear(even tho mine looks new) or add grease....if so what kind....change nylon gear to alumminum one?etc.

    Thanks for any help
    Doug
    This pretty much "Fell" off motor after taking out the 4 bolts on outside of motor. Are these supposed to be connected? Looks like it snapped off! Nylon Gear looks perfect/ new. I did spin it around to check entire gear, but did not remove.

    #2
    Yep - busted. For a replacement, maybe California ebike?
    2nd build, 2018 Crust Scapegoat, BBS02 or BBSHD, Rohloff IGH
    3rd build, 2018 Crust Evasion step-thru, BBS02, Shimano Nexus INTER-3 IGH
    4th build, 2016 Salsa Marrakesh flatbar frameset, BBSHD, Alfine 8 IGH

    Visit the forum knowledge base

    Comment


      #3
      My BBSHD motor rotor snapped a few months ago, observed the same symptoms. I replaced using the Luna motor core. It snapped again a month later. Replaced it with a whole new motor. Yesterday my buddies BBSHD appears to have snapped the motor rotor, although we haven’t tore it open yet, the symptoms are the same. This is getting very expensive and inconvenient. We are in Seattle and there are lots of hills. I’ve changed my riding style to keep it spinning as much as possible, which means I can’t pedal assist at all since the cadence to motor ratio is off, fingers crossed.

      Comment


      • HIGHVOLTAGE
        HIGHVOLTAGE commented
        Editing a comment
        This is probably why you're getting rotor snaps because you're trying to achieve that perfect pedal assist feeling but you're probably putting way too much strain on the motor as a result. The BBSHD was designed with pedal assist as an afterthought, not as their main focus.

      • Scoonie
        Scoonie commented
        Editing a comment
        Bad design, updated but no details... new rotor shaft is wider. Seen on ES.

      #4
      I’m using a Luna Eclipse 42T sprocket and 11-40T in the rear on 29er tires and 52v 30amp. The streets I’m riding on are between 15-25% grade. Is the answer truly that the BBSHD cannot be ridden in these conditions, while peddling, without repeatedly massively failing? Or is this a defect where the motor rotor is keyed on the shaft? And finally, what motor can provide pedal assist and 25% grade at 10-15mph reliably? I don’t mean to sound snarky, but I’ve got 5 bafang based bikes in my and friends hands out in the world now based on my recommendation, and I didn’t disclose to them, nor was it disclosed to me that I should expect and be blamed for peddling my HD motor while cruising up hills. The risk as I understood it was that lugging it overheats the motor and can damage the controller, never that the steel shaft would snap off, and why would pedaling break the motor rotor shaft anyway, that part doesn’t seem to be in the force path of the pedals. Maybe there is a different amperage limit I should use where I could expect to regain reliability and usability, 15amps, 25amps? Has anyone else had these problems and overcome the issue?

      Comment


      • HIGHVOLTAGE
        HIGHVOLTAGE commented
        Editing a comment
        I think the main issue is that you're putting the bike into a high gear to reach a good pedal cadence but also going uphill at the same time. If you don't get it exactly perfect, it's going to lug the motor and put heavy strain on the pinion gear and other parts. It's not the pedaling itself that's causing this, it's the fact that the BBSHD is designed around keeping your RPM as high as possible. If you're not in the right gear and you're not pedaling fast enough to assist the motor (which you wouldn't be because your legs cannot come nowhere near close enough to reaching high enough RPM's) and so you may just be lugging the motor constantly without realising it.

        It's unfortunate but the BBSHD and BBS02 are not the best units for pedal assist unless you just want to "ghost pedal". That's what a torque sensor is for on the Bafang Ultra or the TSDZ2 Mid-Drive, to stop the motor from lugging while trying to get a workout.

        There are some programming setting profiles you can mess around with to get a pseudo torque assist feeling. They should be included with the software in this thread:

        https://electricbike.com/forum/forum...shd-mid-drives
        Last edited by HIGHVOLTAGE; 03-24-2019, 10:17 AM.

      #5
      Mine snapped after 400+ miles of mostly throttle only use. I do not pedal much unless I have to(lazy i know). I ran mine with the 48 tooth Luna Eclipse Chain ring to a 14 tooth cog with Shimano 3Spd IGH. Luna shipped me a motor core and I was up and running in under 4 days. I could not be happier with Luna's response and actions. They even had me ship it to a company in Maryland to do an inspection on the bad core. While I have not heard any updates on what they have concluded, I do hope to hear something in the future. If it fails again in a short timeframe, I will be switching to hub motors. But I do hope to stay with what I already have. Maybe swap out the front chain ring(go smaller) or cheaper to swap out the rear cog(go bigger) to keep those RPMs up. Yes you will loose a bit of top end, but it seems you prefer a more reliable experience. Just mu $.02

      Comment


        #6
        Mine did the same thing and I wasn't pushing it hard at all. Replacement from California E-Bike cost me about 75 bucks. It was a fairly easy thing to fix. I have since dialed back my 'hotrod' settings and no longer pursue power upgrades with hi powered controller, etc.

        Comment


        • HIGHVOLTAGE
          HIGHVOLTAGE commented
          Editing a comment
          When people say "not pushing hard at all", it's not a very descriptive answer. I hear it all the time though. But the reality is that most Bafang owners don't even really know how to properly use their bikes gearing system to shift the bike properly to reduce load off the motor. RPM is the key here. If you can't keep the RPM high and the motor spinning fast, or you're going to run into issues, even if you're assisting with pedal assist. Your legs cannot pedal anywhere near the required RPM's. Also, this can happen as easily as just gunning it up a hill and forgetting to change gears. It's not necessarily something that's going to be painfully obvious to a new rider.

          I always say that you should first try to ride your bike without any motor to get a feel for the shifting and load reduction. If it's too hard for your feet to pedal, it's probably too much work for the magnets and you should downshift.

          I've had my motor for 2 years now. I've ridden it insanely hard at 2500watts but I've always paid close attention to how hard and for how long. Short burst of acceleration? That's okay, but riding around in 10th gear everywhere? That's a no-go imo. You should only switch to high gear after you're already moving at max speed and then downshift back to gear 1 when you come to a stop.

          I'm not saying you don't do these things but it's good to be aware of it because the components are not necessarily designed to take just any load of punishment. It definitely has it's limitations.
          Last edited by HIGHVOLTAGE; 04-02-2019, 07:42 PM.

        #7
        Exact same thing happened to me!
        Does the bad rotor merely slip out of the motor...or are there some other procedures?
        Thanks!
        paul
        Attached Files

        Comment


          #8
          Contact Pax with Luna. He asked for my original order # and date of purchase. Then he shipped out a new core. The entire part u have pictures is sent as a replacement (if still in warranty) and is very easy to swap. It was recommended to re-grease the nylon and metal gears before reassembly. Took about 7 days from time Pax got in touch with me to being back on the road. Hope this helps

          Comment


            #9
            Great idea!
            Any idea how long the warranty is?
            Thanks for the reply.

            Comment


              #10
              Think it's only a year or 2...Not positive

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