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    e-kickbike

    So I haven't even finished my first e-bike build (Gravity DeadEye 27Plus, Sturmey 3-speed, BBSHD), and already the Boy has got me spinning my mental gears on the next one; a Crussis Cross, Kickbikes Fat Max, or Gravity M10 kickbike with a rear hub motor.

    The Crussis: https://www.crussis.com/product/cross-62



    A little less expensive than the Gravity, and available from their lone U.S. distributor, but this is the very top of the Crussis line.

    The Kickbikes Fat Max: https://www.kickbikeus.com/product/fat-max/



    Expensive, and the largest frame by far, but the rear dropout spacing is 135mm, compared to 100mm for the other two bikes, allowing for more motor options.

    The Gravity M10: https://www.gravity-scooters.com/en/...576390610.html


    A very nice bike, and the bottom of Gravity's downhill line. Wood deck with aluminum protector plate below the frame; this thing is overbuilt. No dealers in North America, but they ship internationally at somewhat reasonable rates and seem to support their products with replacement parts and warranty.

    I think the Fat Max is out. It's the most expensive by far, the longest and heaviest, and as nice as a 135mm rear dropout space is, I'd still have to custom build a 20" fat wheel on a 135mm hub, as there are no Bafang fat front wheel kits. Still waiting for a quote from them for a frame-only, but the bike is $300 more than the other two to begin with, and, unlike the Gravity, I've found the Chinese factories where the frames for the Kickbike and Crussis are made. The Crussis will be the least expensive and easiest to get, but I really like the Gravity. They do sell bare frames, but I've asked them if they'll ship one without wheels for me.

    So the general idea is to put a Bafang front geared hub motor in the 20" rear wheel, and see about stashing the controller under the deck or up on the... tube... somewhere. Depending on how much room there is between the deck frame rails I might be able to fit a decent 48v battery in there, or have him backpack it, or mount it to the... tube... where it meets the deck. 500w front hub kits on 20" rims seem readily available, and there should be no problem running one on the rear. Apparently with the right controller they're capable of impressive performance, so upgrades down the road should be straightforward.

    Obviously a pedal assist sensor would be extraneous here, and I'd like to run it without a display at all. Maybe just an on/off switch or key, and a throttle with a basic battery meter, plus brake sensors. Any obvious holes in my ingenious scheme? I know the BBSxx mid-drives can be run without a display, but can't seem to discover how or whether this can be done in a geared hub.

    TIA
    Last edited by DCErik; 07-20-2020, 07:52 PM.

    #2
    That kick bike would scream with a Cyclone 3000, and an HD freewheel on the rear hub. OOH! Running a 3-speed IGH would be pretty darned cool too.

    Jose
    Last edited by DaHose; 07-21-2020, 10:25 AM.

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      #3
      Your heart is in the right place, but without a drivetrain neither an IGH nor a mid-drive is going to be very fast. ; )

      Comment


        #4
        I said freewheel. DOH! I meant single speed. There are plenty of kick bike conversions running rear hub drives, so I think fitting something with a drive gear should be possible. You would need to get creative in the build though.

        Jose

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          #5
          I have been eyeing the old Nuvinci 171 CVTs on e-bay...

          Comment


            #6
            Big shout-out to the folks at Gravity-scooters.com, who were helpful in the extreme in working with me to ship a M10 from Spain without wheels at a pretty reasonable price. This build is greenlit.

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              #7
              Front wheel has arrived from Wheel & Sprocket in WI, and the tire should be rolling up any time now. Bafang 48v front wheel kit (for the narrow, 100mm rear dropout spacing) is processing from Bluenergia via Aliexpress, so now all I need to work out is the best way to mount a battery as low as possible (under the deck looks like a non-starter, so considering two 48v 7ah bottle batteries in parallel, or maybe a single 48v 10.5ah.

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