A Big Wheel Trike

I like wheels, different ways of getting around. An idea to make my own tricycle came to me one day, and when I began googling I actually found a couple of Instructables that helped serve as excellent models to build from; Dr. Qui and Lewis Gifford . Also, hippyengineer, who shared his trike in the comments of Dr. Qui's post.

Now with mine completed I figured I could contribute to the inspiration pile by making my own Instructable. My very first one:)

It was a very challenging, very rewarding process. I was introduced to a new skill/craft/tool in just about every part of this project.

Supplies

Critical: A positive, loving confidence in yourself, and a deep motivation to keep trying, mistake after mistake.

The Frame

Some initial ideas:

Trunk space: enough room in the back for a passenger, and a boombox

It also needed to be an appropriate, comfortable size for me. like long enough.

First I was given an idea to get the frame's dimensions by "drawing" the tricycle out on the ground, using tape. A schematic? A wireframe design? I'm not sure.

So that gave me the first set of numbers for the length and width of the frame and trunk, respectively. I was originally thinking of a trapezoidal shape for the trunk, but that ended up being too difficult; I wasn't able to figure out the angle for the cuts. I went with a square/rectangle instead.

So at this point it looked like a rectangle, with one side wider than the other, which was where the wheels would go, nice and wide. Then I welded a "connecting" bar to that rectangle, that would become the front end of frame.

The Front Wheel

So

The Huffy Green Machine had the kind of hub that I needed; with a spindle for cranks/pedals to be attached, kinda like a unicycle.

But the Green Machine's wheel was much too small. I followed Lewis Gifford's idea and figured out how to build a bigger wheel from that hub, so that pedaling could be more comfortable for an adult and I think to be able to reach better cruising speeds. It makes sense to me that a bigger wheel will roll a greater distance in one full spin than a smaller wheel.

This hub also had a coaster brake. I grinded off the coaster brake arm because, well, im not sure. I thought I wanted to make it a free coaster; to be able to freely pedal backwards, but when watching a YouTube tutorial for that, I realized I actually didn't want that. It made sense to me to be able to pedal backward sometimes on this tricycle. To be able to maneuver in reverse. But, this tricycle *sometimes* pedals in reverse. By that I mean, I can 'drive' in reverse. Other times, I pedal backwards freely, and then something disengages and I pedal in both directions without being able to drive the wheel. I learned that I could mostly fix this by giving the hub a few turns with my hand in either direction. This causes the driver to get somehow get engaged again. I'm not sure how. Maybe it has something to do with my removing the brake arm? I'd appreciate any answers to these questions/advice if you happen to know.

I decided I wanted to have a 29" inch front wheel because that was the size of the spare tire I had. That was one constraint that was simple. I found a 29" hoop with the matching number of spoke holes on the hub, on Facebook marketplace.

I never built a wheel before, never trued a wheel a before. It was a very specific task, very challenging and it was a great adventure. I learned a lot from a few great YouTube videos, and from the nice people at a local bike shop.

I used a part of the frame from the green machine that I wasn't gonna use to make a truing stand. I tacked it on upright to a piece of welding practice sheet metal, and I got it done, colorful spoke nipples and all:)

Now to fasten this front wheel to the rest of the trike

The Huffy Green Machine frame mounted directly onto the hub, on some housed bearings, in between the wheel and where the cranks go on each side. It is conveniently fastened with 4 Allen screws. I cut off this part of the Green Machine frame and welded it to a fork of a scrap bike, making a pretty long fork.

I also took the head tube that that fork slides into, and welded that to my frame. It was very tedious work to find the right angle.

I also moved the brake mount part of the fork a little lower to account for the new length of the fork. Cut it off and welded it to a new position. With that in place, I was able to put in rim brakes:)

The Rear Wheels

The Green Machine had back wheels that I thought would work great. I cut off the part of the Green Machine's frame that the wheels attach to, maybe this is called the axle assembly. And I welded it to my frame, doing my best to make sure they were spaced evenly apart and level.

I noticed the bearings in the wheels were plastic, and I wondered if the wheels would spin more freely and bear my weight better if I found some ball bearings to replace them with. I found bearingsdirect.com, measured the plastic bearings Inner Diameter, Outer Diameter, and width, and sure enough this size existed. and for very cheap. ball bearings are everywhere, I'm learning.

Upon the first test ride, once the trike was more or less together, I felt like the turning could be improved. The back wheels were a bit too wide, making it impossible to go through all doorways. I trimmed off the same amount on each side of the frame, and welded that piece underneath the frame. This gave the back end of the trike a slight incline, and raised the whole off the ground a little more.

The whole thing felt stronger, and was much more maneuverable.

This was also great because before, one issue with the frame was that when steering the front wheel sharply, or letting the wheel turn completely when you get off the trike, the frame underneath the seat would get very close to the ground. But not anymore with the new height in the back:) This was one thing that needed to be considered for a front wheel of this size, and the angle the fork needed to be at for a comfortable ride.

The Seat

How to safely sit on this thing?

The seat from the Huffy Green Machine was too small, so I found a classroom style chair, and welded the chair's base to the frame, taking advantage of the base having screws that makes the chair easy to remove/secure. I reinforced the base using the pieces of chair's legs. At least it looks reinforced.

One important thing about the seat was its angle. For a comfortable pedaling experience, I learned that the seat needs to be at a particular angle, so that my legs meet the pedals of the front wheel nicely. mechanical advantage? I dont know what the word is. So to do this we put the frame on a table, and using some blocks of wood, it was a few rounds of, sitting on the chair, putting my feet on the pedals, getting off and adjusting, until we found something good enough. My instructor/mentor was helping me with this part, holding things in place as I got off and on.

Using a protractor we found that this angle was about 45 degrees from the ground, but truly I don't really know much about how to use a protractor yet, I don't know how accurate that is. I guess it does kinda look like 45.

But after having the seat mount fully welded on, the seat can be screwed in easily with four screws after turning the trike upside down:)

I'd say we accomplished to make the seat angle about 7/10 comfortable. Well the angle doesn't feel off; It definitely doesn't feel too inclined. If I were to do this again, the most necessary change would be making sure the pedals are not too far away. Maybe this could be solved using a smaller wheel, like a 26 or a 27.5.

The Trunk

The Trunk ended up being just a trunk for now, no real passenger seat. It was enough of a feat in the moment. I measured the square part of the frame behind the seat, and traced out a piece of plywood of those dimensions, using a jigsaw. I also cut out a piece of the wood to account for the seat mount, so that the wood would fit flush over the frame on the other three sides.