Human Electric Hybrid
Frame

Because I'm a "Big Guy" I wanted something heavy duty, This included heavy duty wheels to stand up to the cornering forces. Unfortunately heavy duty usually translates to just plain heavy. The complete rolling frame without motors or batteries weighs about 60lbs (ouch).

On this page I will describe the parts used to assemble the frame and show how I built it.
I weigh about 240lbs and I originally figured the complete trike would be about 120-150 lbs; this means the total weight would be around 400lbs. After checking around some I was pretty sure that bicycle wheels weren't going to cut it. Since I also wanted to have hub brakes (either disc or drum) and since hub brakes for bicycles are expensive; I decided to find some moped or small motorcycle wheels.
I ended up using moped mag wheels. As I mentioned earlier the side effect of such sturdy wheels is their weight. These wheels (including innertube and tires) weigh over 10 lbs each.
I was lucky to find a moped repair shop that had lots of spare parts. He let me dig through them untill I found what I wanted. These wheels use precision bearings with 12mm axles and 12mm is the minimum size that can handle being supported from only one side.
The main tube is 2 inch muffler tubing, bent into shape at a local muffler shop. Total cost was $20. The seat is 3/4" electrical conduit from a local hardware store, they even loaned me a tubing bender.
I don't have the pedals and crank installed in this photo, but you can see the clamp that will hold the front part of the boom. I had intended to have the boom assembly go straight out of the frame; however, I messed up a bit on the angle and it was too steep. This setup lets me adjust for just about any angle and length between the seat back and the pedal assembly.
Here is the front part of the frame. You can see how I split the tubing and welded long nuts to it to form a clamp. The nuts are drilled out on one side to allow the bolt to pass freely through to the other side that is still threaded.
The main tube is 2" in diameter(outside) and muffler tubing is 1/16" thick. This means that the inside diamter is 1 7/8", muffler tubing is only available 1/4" increments. The next size down is 1 3/4". In order to get a tight fit I cut a slot out of a peice of 2" tubing and inserted it into the frame. The extra width of the slot allows me to weld a thin strip of metal to the inside tubing to keep it from rotating.
Now I'll describe how I welded the various brackets to the main tube for attaching the front beam, seat, rear suspension, motor, etc.
Here you can see how I took a piece of aluminum and bolted the bolted the front beam brackets to it so that they would be aligned and flat acrost the top. I then clamped this to the frame and welded the brackets on.
I used a piece of 3/4" particle board as a support surface. Particle board is fairly flat and even and doesn't usually warp. Under the main tubing I placed scrap pieces of 2x4, this keeps the tube even with the surface and elevated about 1 1/2" above it. This was just enough room to fit the bracket between the tubing and the surface.
In the upper right portion of the photo you can see the combination square I used to make sure the brackets were at a right angle to the surface and therefor square with the tubing.
Here you can see the basic rolling frame.
Here is the mostly completed frame prior to painting. This is the point where I realized that the crank was too high. The handle bars look a little high here, but that's where they have to be to avoid hitting them with my knees.
A local surplus store was selling rolls of seatbelt material for $5, I bought two rolls to use as webbing for the seat. I divided the tension rope on the webbing into three pieces so I could adjust the tension seperately for the bottom, lower back and upper back.
The foam padding at the top was purchased at a hardware store. It's closed cell foam that they sell for water pipe insulation. I then wrapped it in duct tape to hold it together (It's split along one side) and protected it.

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