With two donor bikes and some other junk, any tinkerer can build a front-wheel-drive, center-steer, semi-recumbent bicycle. (FWD/CS/SR bike for short.) No welding or brazing required! No special tools required! No power tools required (but they can help).
Inspiration for this project came from the following pages:
The $18 Recumbent Bicycle
Build your own recumbent bike, the camel bike
Why? Because I wanted a recumbent, but I'm too cheap to buy one, and I'm too lazy to build a traditional one. It may be ugly, but it's the most comfortable bike I've ridden!
Step 1: Principles and Tools of the Project
This project was originally undertaken with certain fundamental principles in mind:
1) Buy nothing new if available materials suffice.
2) No torches.
3) No special tools.
The good news is that by following these principles, I purchased nothing expressly for this project, and I saved my MAPP gas for more serious projects. On the other hand, aesthetics and perhaps safety are sub-optimal.
The tools I used:
- power drill (not necessary, but it prevents tendonitis)
- metal snips
- wood saw
Obviously, by discarding my principles and using better tools, one can make a much better bike. I dare not suggest that anyone exactly follow my instructions; I offer this Instructable merely to give others some ideas.
Step 2: Choose Donor Bikes
You will need 2 bicycles. One bicycle will provide the main frameset. (I call this the "frameset donor".) The other bike will provide the bottom bracket for the FWD. (I call this the "drive donor".)
The frameset donor should be female. Ideally, it should be large--at least designed for 26" wheels. I used an old road bike frameset that had been sitting around unused for about 15 years.
The drive donor should be no larger than the frameset donor. It may be smaller, at it is in this example. I used a kid's BMX-style bike.
Step 3: Prepare the Frameset Donor
Several parts should be removed from the frameset donor:
- rear wheel
- front wheel (this will become the rear wheel)
- bottom bracket, cranks, etc.
- front brakes (if the donors are of different sizes)
- stem (if it is too short)
- handle bars (unless they are BMX-style)
The fork must be spread to fit a drive wheel. Likewise, the rear dropouts must be pressed closer together to fit a narrower "front" wheel. The fork dropouts may need to be filed to fit the drive wheel's axle bolt.
Step 4: Prepare the Drive Donor
Cut the top tube and down tube from the drive donor, leaving only the rear triangle. You may also remove the seat stays as they seem to have more weight than purpose.
Be sure to file the sharp edges from the cut tubes.
Step 5: Install the Front-Wheel Drive
Mount the fork of the frameset onto the axle of the drive wheel. It may be easier to fit the fork dropouts between the rear dropouts.
Insert a seat post into the front seat tube. Attach the top of the seat post to the stem of the frameset. I used two strips of sheet metal. Depending on the stem you use, you may wish to turn the stem around to avoid interfering with the attachment to the seat post.
You may change the height of the pedals by adjusting the insertion of the seat post.
Step 6: Add Handlebars and Seat
The two most crucial remaining parts are the handlebars and the seat.
Although it is possible to steer such a bicycle without handlebars, handlebars are helpful. However, most styles of handlebars would interfere with pedaling. Therefore, you must use either BMX or ape hanger handlebars. The other possibility is to fashion a tall stem, but that may require special hardware, such as a long stem bolt.
The seat is very important for both comfort and stability. A bad seat is almost as bad as no seat. I made a seat from plywood, then upholstered it with packing foam and vinyl. The plywood has a nice springiness to it. You may need to experiment with various seat designs before finding one that works best.
Step 7: Complete the Bike
Add a mirror. You will almost certainly need it.
Adjust the seat, handlebars, brakes, kickstand, etc as needed. Note that this bike experiences forces rather different from those of a conventional bicycle. You may find that the handlebars and stem come loose more easily than you would normally expect. Also, imperfections in the front wheel are very easy to notice, because it is for both steering and driving.
Step 8: Ride the FWD/CS/SR Bicycle
The hardest part is actually riding this contraption. It is very different from a standard bicycle.
- Your back participates in pedaling.
- Standing starts are difficult. (A low gear helps.)
- Pedaling affects steering. With practice you can learn to steer with your feet.
- If you have no shocks, you may wish to slightly underinflate the tires.
- If the seat is not completely stable, you will lose energy and control trying to keep the seat straight.
- Lastly, people will gawk at your bike, as they try to figure out how it works.