Could this work?

Oddball Matt

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Sep 23, 2020
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Hey guys sorry for not being able to search for much info on this as the bicycle lingo is a bit new to me (non-english speaker) so I don't always know what to search for.

Anyway I got this bonkers idea of possibly building a sort of onewheel bike with the engine inside a hubless rim hoop that would be supported with a metal ring outside the engine/inside the rim hoop by rollerblade wheels. Now, I started thinking about the power transfer and an idea popped into my head. What if I'd weld a loop of chain to the inside of the rim hoop and drive that either directly from the motor output axel or possibly via a jackshaft, either way with a sprocket not a roller? How could I calculate what size the sprocket would have to be (is it viable at all) I read the FAQ thread and judging by what I found this could theoretically be achievable.

Ideas?
 


DAMIEN1307

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Jul 23, 2020
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A one wheeled, motorised bicycle...hmmmmm...The only good idea i could possibly come up with is...Hope you have got a really great health insurance, Accident insurance, and life insurance plan, (burial insurance may be optional if you have enough money going to survivers from your life insurance policy), if you intend to build and ride a one wheeled bike with a motor strapped to it...DAMIEN

EDIT...When you say one wheeled bicycle are you referring to a unicycle?
 
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Oddball Matt

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Sep 23, 2020
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Well I see where you're coming from but a couple pointers: first it won't be a "true" onewheel, there will be a second smaller wheel at the back so it'll look more like a mini penny farthing than a onewheel. Second the rider position will be behind the big wheel not completely on it, and third motorized bicycles are restricted to max 25km/h (15.5mph) here so if I ever actually build this it'll go about as fast as an electric kick scoot so I don't think it'll be THAT dangerous
 

5-7HEAVEN

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Jun 22, 2007
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It CAN be done like you said,
like a mini Penny.

Use the tiniest bike frame that'll accept a 29" fork.

At the rear, use a rear wheel from a Bob trailer
 

Oddball Matt

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Sep 23, 2020
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Probs gonna fab it up from straight stuff if I ever get that far. Just a thought, I like to entertain myself by solving mechanical problems at work (mailman, gets a bit tedious)
 

5-7HEAVEN

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Jun 22, 2007
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I had a Bob trailer once:

https://www.ebay.com/i/133529589360...1291&msclkid=de99726b5e8d1ab553852d1ffa3a0b43

I remember that it used a pneumatic tire, and
the wheel hub accepted a standard freewheel.

Cannibalize a 29" headset, fork, brakes and handlebar from a 29er bike.

Using 2 lengths of angle iron or chromemoly tubing, weld it to the headset at the proper angle.

Drill 2 holes at the other end to install the Bob trailer's wheel assembly.

Weld a seat post onto the angle iron for your seat.

Install this rear engine chain drive kit:

https://www.ebay.com/itm/motorized-...eat-mounting-parts-without-motor/124200328181

Install any engine using a 76mm clutch.

You're done.

Don't go fast; this is a death trap.
 

Oddball Matt

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Sep 23, 2020
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436655f74b8e1d204e.jpg


This is more or less what I had in mind, just add a small back wheel. The whole point of this is to mount the motor inside the big wheel. I'm not expecting this thing to work as a daily rider for years, it's more of a kinetic sculpture type of deal but I do want it to work if I some day decide to have a ride along the canal downtown or pop in the shoreside cafe for a quick ice cream.

I wonder if I could buy a rim hoop somewhere that doesn't have any spoke holes in it...
 

5-7HEAVEN

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Jun 22, 2007
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You're looking at big money there.

What's your budget?

If you don't have mad skills, you'd have to have the skills to design it.....

then spend thousands for someone with those skills to create it.
 
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