"Extrawheel" idea - any thoughts ?

Discussion in 'Push Trailers' started by Meer123, Oct 1, 2009.

  1. Meer123

    Meer123 Member

    Does anyone have any experience using an electric hub motor kit on an Extrawheel (mono-wheel bike trailer) ? If not, anyone have any ideas regarding it's adaptability to be motorized ? I'm curious to know if the common 26 or 700c hub motor kits will work and how it might perform ? If this topis has been addressed already - I'm sorry, I did a quick search and found nothing on it.


  2. linnix13

    linnix13 Banned

    its the same sized wheel as a regular bike tire, the kit would perform the same as it would on a bicycle, go for it there nothing to loose,
  3. Seems quite feasible and a good idea. I was aware of the Extrawheel but hadn't considered its potential as a push trailer.
    The photos and description of the tongue pieces are a little disconcerting, as are the following warnings:

    Do not exceed the speed of 40 km/h while riding downhill (40km/h / 1.61 = 24.8 mph)
    If hit by a car, the Extrawheel trailer will detach itself from the bicycle.
    It may also detach if:
    - it is overloaded
    - you ride at an acute angle onto an obstruction, such as a kerb,
    - you fail to lean the bicycle to the inside while backing up with sharp joint bending

    You can detach the trailer by backing up improperly, hitting a curb, going over 25 mph downhill, or overloading it ! That would not be as much of a concern with a light load of clothing and camping gear, but detachment of the hitch would leave battery & control cables & wires to throw you. Batteries don't hold up well to bouncing down the street. The torque of the motor might mimic the forces of an overloaded trailer that has apparently been designed to detach in atypical circumstances. It's advertised as the lightest trailer so maybe the high potential for detachment is only a result of minimal construction due to weight concerns.
    I'd like to inspect the real article instead of looking at pictures. Maybe it could be reinforced before being trusted as a drivetrain. I doubt that I would trust attachment to the axle merely by spring tension on those frankenstein bolts they call Extrawheel nuts.
    We could use input from someone who has used one of these, and from electric afficionados.

    My suggestion is to keep your battery weight as low as possible (in lbs. AND inches) and (as much as possible) keep the batteries ahead of the tire-to-ground contact patch. The idea is to minimize any top heaviness which puts torque stress on the flimsy hitch. It's max. load is 30-35 kilos which would apply more to the batteries slung from the frame than the hubmotor which is supported not by the frame but by the spokes and tire. 30-35 kilos X 2.2 lbs. = only 66-77 lbs. Also consider that any torque applied to the wheel results in the same amount of countertorque, so the thin, flexible, spring steel tongue pieces will have to resist torque effects on the hitch in addition to the forces for which it is barely strong enough to manage. I would be at least initially cautious about using any of the more powerful hubmotors (due to their torque) or large batteries (due to their weight). I'd go for a lower wattage hub that would give greater range by 'allowing' or 'requiring' (depending on your point of view) more rider power input. I wouldn't worry much about the larger hubmotors if the wheel was a little further back from the hitch, if it used a seatpost hitch, if the tongue pieces were more rigid and substantial, and if the power was rolled on slowly and smoothly. Remember electric motors provide their greatest torque at startup, unlike gas engines that have little power til they reach their power band. My personal advice is to proceed with much caution.
    Last edited by a moderator: Oct 9, 2009
  4. BikeMan

    BikeMan Member

    Here is a bicycle wheeled electric hub set-up.You can buy the plans for this kit.
    What I like about this electric pusher set-up is the fact its your call on top speed and range just by adding more batteries.


    And to here is a video showing a bike using the same parts as the bike pusher above.Also same guy made both.Whats really cool to is its your call on speed and range.


    Finally here is a video of the electric bike pusher in action.It takes several minutes to bring up vid???

    Last edited: Oct 16, 2009