Introduction: How to Build an Ergonomic Cycle Truck
I got tired of falling over when climbing off my old bike fully loaded with cargo. I looked for one that had all the things that I needed, like easy dismount , full MTB gears (for climbing hills with cargo), and a front rack that would not affect the steering when fully loaded with 50lbs or more. I could not find one at any price.
At the same time someone told me that the bike was too short for me. So I moved the seat back by making a special seat post, and I discovered that I could sit up straight (to relieve my carpel tunnel syndrome) and still apply my weight to the pedals, because the crank was slightly forward. 4.75 inches is 60 degrees from the seat; just like the old bikes made for sitting up straight. I still need to lean forward a little to climb hills. This crank forward also encourages me to pedal in circular motion.
So I worked a long time measuring and drawing to invent this one. And it took me a couple years to eventually build it.
It amazes me that most people just do not understand bicycles. I have writen so much about these machines that there is no excuse for not understanding why bicycles must change.
There are people that reject this frame concept merrly because they have not seen this kind of frame beofore. Obviously these people need to learn to think! try this book: "Lateral Thinking: Creativity Step By Step" by Edward De Bono.
When I was designing recumbent bicycles I discovered the ergonomic power angle. When you want to design a bike just for you, measure for a 40 degree or more when climbing hills and a 30 degrees to the back of the seat for cruising. You can move around on the seat to get the right position.
Recumbent bicycle seats are usually set at 35 degrees with 5 degrees of adjustability.
If you use a 24 inch wheel it will be like a lower gear that is good for hill climbing with cargo.It is better to have a lower gear than you need so that you can spin the crank fast, like bike racers do when climbing.
If you use disc brake in the rear and have a steep steer tube angle, you could switch wheels later and still have a reasonable steer angle.
See how I put a motor on it:
To calculate seer angle try this one http://www.kreuzotter.de/english/elenk.htm
Find more info on bicycle design on my non-profit blog abut Utility Cycling Technology:
Step 1: Fixtures
The rear axle is higher than he front. A 24 inch wheel (that will give you an effectively lower gear) is one inch lower than the 26 inch.
For the second bike I will be using a fixture for the bottom brackets that will help keep the two halves of the frame straight, when clamped together for tack welding.
These hold devices should be mounted on a metal flat bar at least 5-1/2 inches wide x ¼ to 1/5 inch thick. Do not trust wood to be square and straight.
A frame jig of 1/2 inch steel plate would be very nice to have.
Step 2: Steer Tube Extension
The first thing to do is find a BMX front fork with a about 1.3 inches of rake or more. Then add and extension using an angle bar to hold it in place. You can buy threaded steer tube if you don’t want to use a thread-less head set. Cut the threads to fit the stack height.
But if you need a disc brake on the front, it would be much easier to buy a Recumbent bike disc fork off eBay and insert an extension. Better to use a rim brake for emergency only on the front, and use a really good disc brake on the rear. Hydraulic if your going to haul really heavy cargo down steep hills!
Steer tube 1 inch OD x .834” ID x .083” wall (use thread less headsets or buy a threaded steer tube )
Head tube 1- 3/8th OD x 1.185” ID x .095” wall
Steer tube 1- 1/8th inch OD x .955” ID x .095” wall
Head tube 1-1/2” OD x 1.334” ID x .083” wall
Step 3: Construction
I used two mountain bike frames; the rear triangle of one and the down tube with bottom bracket still attached and some of the seat tube for the front derailleur. (At least 4.75 inches) Set the head tube angle with plywood cut to the right angle or use a protractor square.
I was going to use the cut head tube as a guide, but decided that I needed a steeper steer axis for less trail without adding more rake. I like a small amount of trail (1.5" to 1.7") for slow speed hill climbing, because more than two inches will create too much wheel flop!
Grinding and hand filing the compound joints can be a challenge. A Tube Notcher jig would be much easier. But if you’re doing just one bike it's not worth the money.
If your using old rusty tubes, wash them out with Ospho rust killer.
Add heavy duty rear disc drop outs after the frame is done or at least tack welded.
Check alignment with string.
If you’re going to pay someone to do the welding, find someone experienced with a MIG welder and that knows how to keep the frame from warping. i.e.: cool each joint before going to the next…. Do the top of one side , then the bottom of the other side, then bottom of the first and finally top of the second side. Don’t do the sides until all the tops and bottoms are finished.
Some people say that TIG welding is much better, but it is very slow and will cost you much more. Fillet brazing is good if you’re going to do it yourself.
Step 4: Racks
I had to make a stainless steel rear rack because I did not build one onto the frame when I was building it.
Rear disc brake drop outs can be brazed in after you’re finished. Then build a rear rack right onto to the frame, making sure it clears the disc brake.
I have had way too many aluminum racks brake. Use 1/2 to 3/8th inch thick wall (.083" or .095") tubing of 4130 air plane steel. I use square tubes when possible because round tubes are harder to join to round tubes. But the round tubes do bend easier. Thin all tubing may have problems bending.
Flat bar works fine for the front, but angle bars may work better. I have seen one made of 3/4 inch flat bar But I used 1.5 inch by 1/8th inch on mine. But soon discovered that it was not wide enough to keep the box from wobbling side to side.
Step 5: Handle Bars
I wanted ergonomic bars so that my hands would not be twisted all the time, and my carpel tunnel syndrome would not hurt.. Note the forward holding position for leaning into the pedals. Weld them right in the jig.
7/8th " OD x .745" ID x .065" wall
with a small piece of 1" OD x .884" x .058" wall over the center of the tube to be clamped.
I had to gouge out a recess in the ply wood for the extreme thickness of the center tube. so that the whole thing would sit flat on the jig for tack welding.
Step 6: Finnish
After finishing, the bottom bracket threads may need to be reamed out by some one that has the tool. Clean the threads with Naptha before baking on the powder coat so they will not get clogged.
The plastic fenders can be bent by warming them above your kitchen stove, be careful not to burn them.
Note how the fender holding rods are bent around the disc brake.
I tried spray paint, it was a waste of money and time. Epoxy wood sealer may work a bit better, but a good baked on powder coat job is worth whatever the price is.
Note the second to last photo: The foot can be closer to the front wheel that I showed in the plans.
Think about using moped tires on a bike like this. A 16/2.25" moped tire fits on a 1.25" x 406mm (20 inch) bicycle rim.
These tires are so much stronger than even a BMX tire that I was able to ride to town and back with a load of cargo, at only 7.5 PSI ( I had a slow leak and did not know it). It was very hard with the extra rolling resistance, but that's how strong the side wall is. the tread will last me for years. read more here: http://commutercycling.blogspot.com/2016/01/bicycletires-do-not-do-well-on-really.html
Step 7: Other Ways to Build a Cycle Truck
You can keep the frame in tact, and weld an extension directly to the old head tube , Or remember to cut the top tube out AFTER the new lower cross tube is welded in place.
Use the old head tube to hold the new longer head tube in alignment while welding, by cutting the old head tube in half and clamping the new one to it.
The less you have to cut away the easier it is to keep the frame straight. See more info here.
1 x 2 inch 4130 Rectangular Steel Tubing is the best thing you could possibly use to for the bottom tubes on the long bikes.
How to make a better rim pulley: http://commutercycling.blogspot.com/2016/03/custom-belt-drive.html
Now for intalling a motor, with complex wiring: http://commutercycling.blogspot.com
Step 8: The Future of Transportation
Waiting for the middle class to change their 'fuelish ways' may take too long. People will not stop driving cars until they have no money. Then it will be too late to buy an expensive cycle truck, because the environment will be out of control by that time. If you want people to use these machines, you have to make them cheap enough for the people that need them now.
I want several people in every town to build them out of recycled bikes, it is going to take a war time effort to get ready for a world with out oil. If I could sell my paintings I would buy more tools and materials to build more bikes, and give them away to people that need them now.
Step 9: Think About It Before You Start Spending Money
The next utility bike I build I will set the steering angle at about 65 degrees because the extra weight on the front causes the steeper steering to shimmy. And I would also add more tubular supports on the sides of the front rack., similar to a German postal bike I saw. To keep the box from wiggling. Then the rear should have suspension with a 20” drive wheel. And finally I would lower the seat a small amount [and push it back a bit] to make it easier to put my foot down on the road at a stop light. This would work only if you have a motor because it would be harder to press the pedals hard enough. See crank forward cruiser bicycle [an excellent bike to turn into a utility bike].
There are many ways to build an electric bike. if you do not understand how to engineer for hill climbing you will waste a lot of money.