This is a big Big Wheel. By the time my little brother got a regular Marx Big Wheel, I had surpassed the weight limit and I never got to ride it. A long, long time passed and I made this one with a 29" unicycle wheel in the front and 15" golf cart wheels in back. The frame is silver brazed chromoly and the fork is machined from aluminum plate.

 The chair is what's left of an Eames shell chair by Herman Miller. It adjusts forward-to-back in one inch increments to suit kids up to, I dunno, eight feet tall? This trike spends a lot of time riding two- and three-up.
This one I call the X-plane. The nylon BMX mags are marked "Stealth", the Schwinn Varsity frame is pure Cold War tech and style, and its riding qualities X-plain why more bikes aren't made this way! It's the result of some of my experiments about adaping normal bikes to cargo-carrying purposes. The tilt joint on the front axle is fortified with a pair of Timken tapered roller bearings, and the axle itself is a piece of drill rod that seemed pretty corrosion-resistant at first. I punched out the original bearing races in the mag wheels and pressed in some nice sealed cartridge bearings. I fitted the X-plane with a longer than usual "fork" to buy a little more room between feet and front wheels. To get the bottom bracket back down to a more normal height, I replaced the original 27" wheel with a 24" coaster-braked unit. I originally equipped this bike with 14-apeed front and rear shifting, but one ride assured me that the bike would not be spending much time going fast, nor would its rider often have a hand free for shifting.
This is what I refer to unimaginatively as the Chair Bike, whether or not it is sporting its removable skid with chairs attached. This bike was originally constructed-- in great haste-- for the Cycle Messenger World Championships 2003 cargo race. Later I fitted it with chairs and a fancy paint job for the purpose of hauling people into and out of a wedding ceremony at a park. More recently, it has been a huge favorite among the neighborhood kids, who have endowed it with quite a bit of wear and tear. It's going to get new upholstery and paint in time for the Maker Faire in Austin. I made the frame from mild steel tubing brazed with brass. The deck is ordinary plywood with a handful of angle aluminum rails to keep things aboard when operating as a flatbed. The chairs came from Goodwill. I butchered 'em up and reinforced them with birch plywood gussets that I cut with a computer-controlled laser! There are seven gears to supplement a winning attitude.
The frame is simple, but plenty of CAD drawing went into making the thing more or less straight and level. There are two brakes, one on the front wheel and one on the right rear wheel. The doodad sticking up to the right of the rear wheel is a fork block, which can be used to tow a regular bike (simplifying logistics). It has also been used to harness a second rider as an auxiliary power unit.
 
The yet-to-be Chair Bike in its first major outing at the 2003 Cycle Messenger World Championships cargo race. That's veteran rider and rapscallion Matt Messenger at the helm hauling a concrete block, a couple of bundles of newspapers, a hay bale, and several other items including a Canadian lass.  

This is the Sidewinder, a bike with one-sided wheels like a car's. The front wheel runs more or less on the centerline, but the rear wheel sits over 3" to the left of the frame. It feels bent but still quite ridable.

 The chain runs on the "wrong" side of the frame but the right side of the wheel.
 

Tire and tube repairs were never easier. The wheels don't have to come off!

 
Here's my adaptation of a Boeing plant trike. The frame retains all the patina of many grubby years on the factory floor, but its details are now all hot rod. Those are ATV sand slicks in the back. riding on hubs and an axle I had to make from scratch. This is one of the Boeing trike's stylish hubs, which I CNC-milled from a chunk of very fancy aluminum that was also aerospace surplus.
Introducing the Red Bike, one of my longtime companions. I didn't make the frame of this bike, but I did machine almost all the components using 2.5 axis CNC milling and a manual lathe. I am very tall-- six feet eight-- and very heavy (over 300 pounds) so I took it upon myself to build up a bike that was truly a match for the demands I made of it. I made this front hub to allow bigger bearings and a larger. sturdier axle than money alone could buy.
I made this rear hub to incorporate a massive axle and a needle roller bearing on the right side, because the freewheel thread limited the size of ball bearing I could use. The 6-bolt pattern on the left is not for mounting a disc brake, but rather for retaining the ball bearing cartridge, since the bearing on the other side has no axial retention. Pretty. Heavy. Rigid. And a little complicated to explain. When I made the brakes for this bike, they overwhelmed the ability of the existing fork crown to clamp the legs and to resist the high bending loads involved. So I made a fork crown and handlebar stem that join together with a rod to reinforce each other. In this picture, the fork brace, brake arms, brake booster arch, and fork crown are all of my own design and manufacture.
I machined the chainring spider, chain guides, and a sassy outboard bearing bottom bracket to accommodate a beefy BMX/freestyle crank. Behold my stainless steel perimeter defense pump. It weighs about one kilogram, it inflates tires, and it can teach dogs tricks (e.g. "roll over", "play dead"). It is also able to clean windows for car drivers who are having trouble seeing clearly.
 

Detail of the handlebar stem I made as part of the reinforcement scheme for Red Bike's front end.

All photos by Chalo Colina, copyright 2007