A Light Sport Recumbent Bike
The recumbent bike has always seemed an interesting project. In 2007 daughter Sara saw a $3000 European design that would lend its best features to a homebuilt recumbent so she could learn Tungsten Inert Gas welding. The ergonomics of the bike could only be described as impressive. After considerable research, we bought a new 18-speed men's 26-inch bike for essential functional parts and some aircraft tubing. When it was complete, our recumbent had cost us about $300.00 and it is a great ride. I was so satisfied with the result that I had to build another for myself. Knowing dimensions, materials, process and photos made it less of a research project. The actual second build took about half the time. The tools needed assume reasonable access to a lathe, gas or TIG welder, a band saw, a drill press and a disk grinder. It'd also be good to have a light Dremel tool for salvaging bike parts. Feel free to copy what I have done here if you're interested.
The main frame was replaced with a single 4130 aircraft grade steel tube. The rear frame retained suspension while the cranks were moved to the front. The 26-inch fork was shortened to a 20-inch. Functional tubes that held bearings were reused and one frame member from the original men's bike was re-used for a seat back support.
Original dimensions were ink marked full scale on a white table top to arrive at curves needed for the frame tube. Frame tube and crank tubes are 4130 aircraft tube. Original sprockets, cables, shifters, gears and brake mechanicals were re-used, less the seat, front wheel and tire.
Additional chain, an idler sprocket, return guides & an old set of handle bars were obtained for the wide spread grips. A new 20-inch wheel, tire & tube were also purchased.
Lastly, a fiberglass seat had to be made to provide a light, continuous support from the seat bottom to the shoulderblades. I made a wood form, then a mold which yielded the finished fiberglass product.
The suspension recumbent doesn't impose stress on the back, arms, neck or wrists, yet it's a lot of fun to ride and should become a real good distance bike.
Making a strong, lightweight seat from fiberglass reinforced with aluminum tube was also part of the process. A seat mold was made that permits multiple layups.
Of course, the bike needs a transport rack to take it thru town to the Q.C. Mississippi River bike trail.
Note that it's supported & secured at the frame's c.g. & held balanced at the tires.
A simple construct that anyone can make with angle and round stock.
For those who've sent email inquiries about the Light Sport Recumbent,
ThThis is it, finish-painted with a tote rack and soft sider.... ready to carry ice, pop, camera and rain gear.
You are welcome to copy what you see here and If you have questions on construction of this bike, just ask.