The Speaker Guy

Not a mere cardboard cover, this is 100% unicorn bike! Charlie sports a plywood frame and eccentric wheels, Yes, he gallops and prances as he rides down the street. This limits his top speed to a slow jog, but he mesmerizes those he see, often getting "WTF", "SIC", "no Way!" exclamations from those he passes.

Charlie and his pal Pearl have a facebook page with more pictures and videos of them in action.

www.facebook.com/charlie.unicorn.bike

Floyd

I like it... I wondered about the steering, then saw the hinge. must be a hoot to ride.

Flying Merkel

I demand a video!

The Speaker Guy

There's a couple videos on his Facebook page, and some in YouTube sound by searching for makerfaire charlie unicorn bike. It is a bit hard to ride, as the geometry of the front end changes constantly. Charlie has the cranks too close to the front wheel, and no chain tensioner. Pearl fixed those problems, but her cranks are a bit too underneath the saddle. Sigh, hard to get right without a good CAD program and a CNC to whip out new parts.

Rong

How on earth did you build those wheels? I have to assume the spokes are all varying lengths in order to get the hubs offset like that, but how did you figure that out? Sorry little pea brain is hurting itself trying to figure this one out.

Seriously ludicrous bikes - love em! And if you could have Taiwan mass produce them you could have every little kid who could ride a bike wanting one. Personally I'd like a Camel.

Artkansas 

That's quite a bike. Well done!

The Speaker Guy

I did a CAD drawing (Visio) of a cross 3 laced wheel. I then dragged the hub off center, and readout the new spoke dimensions. I paid $25 for 75 spokes from a seller on EBay, plus shipping. Awesome deal.

bud16415

Years ago when I was a kid about 1965 a neighbor kid sat on the floor of his garage for about a month cutting re threading and fitting 26 inch spokes into a 24 inch wheel. I forget what the offset was but they ended up in the 26 inch Schwinn frame. To this day I have no idea why he did this, but I do remember riding it and riding it down a hill. Starting with both offset hubs low you would just go up and down but because the tires must have been different as you went it started to rock front to back and at about 15 to 20 MPH on a hill was really something. It came out of the barn every memorial day to ride in the parade for about 20 years and then I never saw it again.

Very nice job on this one!!!

The Speaker Guy

Another way to do the spokes was shown to me at MakerFaire bay area 2011. There was an alt bike collective, seemed to be run by a Santa Claus-ish man, who rode a large purple scooter with 16" wide or so sand tires, with an eccentric rear hub. This was propelled by pumping. Anyway, he showed me some wheels he laced eccentric by simply adding Z bends to the spokes in lieu of the head of a spoke. It seemed you could not crank the spokes very tight, but it did the trick for a goof off bike.

NukeouT

I preferr "Unicorn The Tall Bike" personally.

https://velospace.org/node/33349

StephenH

When you steer a bike around a turn, the front tire goes farther than the rear tire, so even if the tires were identical, the wheels would get out of sync as you rode.

The Speaker Guy

We more or less ignore the sync of the wheels because you really do have no control on it. However, when riding very slow, a prance (wheels in sync) is best due to the perceptible shift in velocity, and it is easier for people to see the action. At higher speeds, a rocking motion (wheels out of sync) is easier to handle. If you let the speed creep up on a hill with the wheels in sync it feels like the bike wants to jump off the ground.

bud16415

Good point.