Cut-Rate Recumbent Bike

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Finally, we went ahead and added extras — like headlights, a rear fender, toe clips, and safety flag — to make the three-wheeler practical well as enjoyable.

Click here to see complete materials list.

The Frame-up

We'll admit it ... at first glance, the recumbent looks like a pretty complicated workshop project. But if you study the "exploded" photograph, you'll see that the bike's chassis simply consists of two parallel frame rails — and a crank post — fastened to a dropped front axle ... and that these main components are held in check with wishbone radius rods, fore and aft. An antiflex hoop, affixed to the free ends of the frame rails, also serves as a fender and generator mount ... and a similar support — welded just forward of the rear tire — provides a solid point at which to attach the brake caliper.

The seat — merely a tubular frame that's crisscrossed with plastic webbing — is clamped to the front axle through a pair of 2" X 2 1/2" coil springs, and is supported at the rear by a set of telescoping shocks that are bolted to the frame rails (see the construction detail we've provided).

In order to assemble a recumbent bicycle of your own, you're going to need the tools and materials called for in our lists, plus a flat table or workbench upon which you can clamp the tubular parts while welding the frame. Keep in mind that you can hold costs to a minimum by scrounging — perhaps by salvaging from trash — bike frames and parts of various sizes, since many of the components used in our design were taken from junked 20" and 26" models.

Since the chassis is the base upon which all the other parts are mounted, it's important that you build it as accurately as possible. Start by bending your two frame rails (see our specifications) to create the rear "kick-ups" shown in the illustration. (A 1"- conduit bender will cost you about $35 ... but you might be able to borrow one from a local electrical contractor in order to make the several necessary arcs.) Then form the 40 degree front-axle drops, and set aside the four radius rods, the crank post, and the two 1 1/4" X 2 1/2" pipe steering-head tubes.

The angles in the front axle are critical to the bike's handling, so that assembly's left and right sides must be symmetrical. To achieve an accurate match, you'll need to cut contours in the ends of the axle tube with your aviator's snips — and verify the results with a dial protractor — to assure that the head tubes meet the axle at the required seven degree axis inclination and 12 degree positive caster. (When making your final measurements prior to welding, the axle tube should be clamped so the drops are perpendicular to the table you're working on.)

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