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Vibration at high speeds BBSHD

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    Vibration at high speeds BBSHD

    I have a BBSHD on a full suspension MTB with a 48v 10ah battery. I built this bike about 3 weeks ago and only have about 120 miles on it. This is my first e-bike build so I don't know whats normal or not. My top speed is about 30mph but when I get over 22-25mph I get a vibration in the pedals. I was thinking at first it was my chain not completely fitting on the new chain ring but after inspecting the chain thoroughly I'm almost positive it's coming from the BBSHD. Is it normal to get a vibration like this? If not what could this be? And is 30mph about the top speed I should expect?


    P.S. Happy forth everyone!! Be Safe

    #2
    Here are pics of my build

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      #3
      Does the vibration happen in all your pas levels at that speed? I get a small vibration in all pas levels at about the same rpm.

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        #4
        30MPH with the 48 is great. About right. A bit more with a 52V here.

        Can you suspend the wheel and get the vibration to happen? I'd be looking for something else. Had a fellow convinced it was his motor and it was a chain guard vibrating at speed. Yes he did sort adding a chain guard.

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          #5
          It goes away if I stop pedaling or change to the next pas up. I am using the 1-5 pas. I'm guessing it has to do with motor rpm. Happens about the point I can't keep up with the motor speed. Top speed here with the 42 is about 26-28 mph. Would love to try a 46, sure would be nice to know someone that a could just swap my chainring out and not replace the complete Luna chainring. Wink wink Louis.

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            #6
            I'm happy with the 30MPH and I can get a bit more in the right conditions. I do get the vibrations on PAS and just full throttle. Iv'e tried different gears and still get the vibration although the speed I get them varies a little. I tried suspending the rear wheel and the vibration went away. I've thoroughly checked the chain and pedals and I'm convinced it's coming from the motor. I was reading a post on Endless Sphere from someone who re-greases the Bafang mid-drives after the first hundred miles. He mentioned one out of every ten he gets will have a vibration at high speeds due to being light on grease and re-greasing usually fixes it plus helps them all from getting vibrations down the road. although I consider myself mechanically inclined I'm new to Bafang and E-Bikes in general so I don't know if this is really an issue and if it is should I attempt taking the motor apart to do. BTW let me say that other then this miner vibration I love the BBSHD. It's just a awesome little machine. I live in New Orleans and commute though the french quarter.
            E-Bikes are new here and I get asked everyday about my bike. I send them to Luna Cycles.

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              #7
              Well I suspect you hit on the answer. I'm not sure who the post was written by but that is certainly a good direction to take. It's quite easy just some patience. There's a take down thread on ES. The only oddity is dropping the clutch back into place. It's in the thread. Just be careful and patient. I'm using the Mobil aviation grease talked about on electric-bike blog.

              Don't know the poster on ES but it's a good direction.

              https://endless-sphere.com/forums/vi...lutch#p1166400

              https://electricbike-blog.com/2015/1...and-not-heard/

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                #8
                My next question was going to be what type of grease do you recommend. Thank you for the help. I'll let you know how it works out.

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                #9
                Before you open you BBSHD... Do you get the vibration at the taller rear gear at full throttle? If it's the motor you should get the vibration on a specific motor RPM not a specific rear wheel speed. But since you can get the vibration to occur while the bike is suspended I would try to do it again but with the rear brake applied (brake sensor unplugged of course) to create stress in the motor gears.

                I would also recommend looking at the chain movement, rear triangle (swing arm) play, spokes, rear hub play and, rear axle play in the dropouts rear cassette and those freewheels on the derailleur arm before opening the HD. takes only a few minutes.

                If it's not the issue and it's is coming from the motor....use this link: https://electricbike-blog.com/2015/1...and-not-heard/

                The recommended grease is the Mobilgrease 28


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                  #10
                  It always pays to add some lubrication.

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                    #11
                    i just noticed same issue today im now on my 630km on my bbshd bike when i'm on pedal assist "any level" when i'm on highest gear + hard pedaling and at 40++ kph i can hear strong noise & vibration from the motor and it stops when i'm throttling :(
                    Last edited by pcliteuser; 07-08-2016, 08:25 AM.

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                      #12
                      I love the beat up cardboard battery box on the rack! Now that's what I call stealthy!

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                        #13
                        When you are riding next time, look at your chain line. Is it straight at your particular gear? I have BBSHD and when I have a chain line thats a bit slanted, I feel vibration through the pedal. But its not from the motor but the chain vibrating side to side ( not violently but a 5mm swing). This does go away when the rear wheel is suspended because the chain has no tension.

                        Although, I did repack my steel gears with mobil 28 grease.

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                          #14
                          i can still hear and feel the vibration at high speed even after applying grease in the chainring side of the bbshd motor, the weird thing is it only lasts for about 2-3 seconds then it goes away.

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                          • pcliteuser
                            pcliteuser commented
                            Editing a comment
                            i took my bike for a spin and i noticed that the vibration noise is there doesn't matter which gear you're in

                          #15

                          Yes, it's normal. Similar to the sound made when the bike is pushed backwards. I've ridden 3 different BBSHD units and they all do it when the motor reaches it's maximum rpm for the amount of current drawn.
                          For example, if you're in PAS 3 and the vibration starts, you'll notice that it goes away by upping the throttle, until you go faster and it hits the max rpm again.
                          You'll also notice that it varies how fast you can go by how charged your battery is. With a fresh 52 volt 20ah battery, I can pedal to about 37mph before it tops out and starts to vibrate.

                          A lot of people have claimed that the BBSHD seems like it should be able handle way more than 30amps. Mine gets quite hot running 30 amps continuous.
                          'Continuous' as in 10+ miles further than a test ride to the corner convenience store.

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