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BBSO2 touching the frame of my bike

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    BBSO2 touching the frame of my bike

    I recently installed a bbso2 kit on my bike and i've seen videos where they put shims to make a little space between the motor and the bike frame. On my bike it touches the frame but i see absolutely no problem with running it this way. I guess my question is: Should I get the shims/spacers and remount the motor with those or can I just leave it touching because there's no moving parts that get obstructed by that. in other words I see no reason for the shims unless someone can explain why i need them. Another thing is that my bottom bracket is 71mm and there's already 3mm space that i have to accommodate for on the mounting side of the motor so i had to get longer bolts with spacers/washers to fill in that 3mm space. My concern is that if i put more shims to move the motor even further away i'm gonna have problems on the mounting side. I hope i'm not killing the motor because it's touching the frame a little bit =)

    #2
    As far as I know, the usual reason people shim their motor is to allow the motor or chainring to clear the frame, or possibly to improve their chainline. If everything works, shimming is not needed or even desirable. If it bolts up without shimming, but you want to improve the chainline, I'd try to correct it by using a different chainring, or by shimming just the ring - not the motor. YMMV.

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      #3
      Originally posted by Poco Askew View Post
      As far as I know, the usual reason people shim their motor is to allow the motor or chainring to clear the frame, or possibly to improve their chainline. If everything works, shimming is not needed or even desirable. If it bolts up without shimming, but you want to improve the chainline, I'd try to correct it by using a different chainring, or by shimming just the ring - not the motor. YMMV.
      Yeah that's what i did. I shimmed the ring. Ahh now i get why people shim it. not because it's bad for it if it's touching but to make space for the ring...
      Thanks man

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        #4
        Sorry - I misread your post. Since the motor IS hitting the frame, I would probably shim it away a slightly. With frame flex, I'd be concerned about putting force on the motor housing. Dunno...

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        • JPLabs
          JPLabs commented
          Editing a comment
          YES! You don't want side load taken by the housing, but by the center, or it will distort the housing. You only need a tiny clearance.

        #5
        Originally posted by Poco Askew View Post
        Sorry - I misread your post. Since the motor IS hitting the frame, I would probably shim it away a slightly. With frame flex, I'd be concerned about putting force on the motor housing. Dunno...
        hmm good point there. The housing does hit my frame and i have 2 spacers to be able to put the lekkie ring on. maybe it's better to shim the motor just a bit like 1 or 2mm and remove one of the shims from the lekkie bling ring. Anyway thanks for the advice i ordered the shims
        Another question will these fit the bbso2 because they're maketed for the bbshd https://lunacycle.com/parts/bafang-p...ting-4-pieces/
        Thanks Poco
        Last edited by intramorph; 11-14-2017, 12:19 AM.

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        • ykick
          ykick commented
          Editing a comment
          Yes those will work fine with BBS02 as they share the same spindle diameter as BBSHD.

        #6
        I needed some room between the motor and the frame for brake and gear cable housings, so, I used a piece of leather for a pad. Another advantage is that should the bottom bracket nuts come loose the motor won’t bang on the frame.

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        • JimOst
          JimOst commented
          Editing a comment
          I have the same condition on my build. I have some leather in the shop but also have some dense closed cell foam which I'm thinking of using, I'm concerned the leather will hold water etc.....

        #7
        Epoxy putty makes a nice fitting spacer between motor and frame. Tape or wax frame so it won't stick. Form to fit. Sugru is rubbery if you prefer soft, but rigid is better IMO.
        Last edited by JPLabs; 12-06-2017, 02:02 PM.
        Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

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          #8
          I use chunk of old tire tread for a bumper/spacer.

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