Speedmachine Clone

This recumbent is my third homebuilt.

My first was a short wheelbase, which really count as two or three bikes, as I am still revising it.

My second was a Tour Easy Clone. It is nearing a year old and is my main ride. Things are much easier to build when you have, and follow, plans.

After riding for a while, I found that the claims of instant speed for a recumbent, etc, were not real. I ended up about as fast on my Tour Easy as I am on my DF road bike.

My goal, for some time, has been to ride 20 miles in one hour. With the bikes I have, I can't do it. I know about riding more miles and "no pain-no gain", but I'm 61, have only so many hours to ride and am not to hopeful about improving the "engine"the required 20%.

The remaining speedier alternatives seem to be low racers and/ or streamlining.

For some time, I have lusted after a low racer. While planning this project, I considered cloning an M5. a Reynolds Wishbone RT, and others. But, a true low racer is pretty impractical for anything but racing. Also, unsuspended recumbents really bang the hell out of you.

Anyway, while searching the web for recumbent stuff, I came across Warren Beauchamps writeup of "The Street Baracuda" http://www.wisil.recumbents.com/wisil/streetcuda/streetcuda.htm. A suspended 20/20 recumbent he had built.

I decided to build one generally like his, but a 26/20 wheel size. Also, he used a steering tube suspended fork, which was WAY to rich for my blood. I chose a mountain bike type front suspension.

Using his plans, I drew The frame on my front sidewalk and placed the wheels and other parts in position to determine feasibility. The rear never looked quite right, but I got things where they "about fit".

Off to the muffler shop, I copied the frame onto newspaper, and the owner was able to bend 2" pipe into the shape I wanted. The bends are not as beautiful as mandrel bent, but look okay to me.

Next, I cut the holes and brazed in the rear swing arm pivot and the head tube. I made a fixture from an oak pallet to keep things square.

The rear suspension remained a problem. I couldn't get the shock to fit under the rear part of the frame and keep things low enough. Somewhere in there, things began to "morph" towards the Speedmachine design. I finally decided to cut the rear portion of the original frame off and go towards the speed machine.

The rear swing arm was the most complex project I've tackled to date. In spite of my best efforts to fixture everything, I had to break several brazes and redo them after grinding a bit here and there.

The seat was also an adventure. I was going to make a open mesh sling seat, but became enamored with the Speedmachine euro seat look. Again, my miserly ways cut in and I made one out of plywood.

I didn't love it, so I figured out an alternative, using my SWB seat. It will do for first rides. Later I'll make on out of fiberglass, using the wood seat as a pattern.

After riding some miles, I was disappointed in the speed potential. It appeared that the chainline required by the front suspension fork was robbing power (there were two chain turns of near 70 degrees) . Also, you could hear the rear suspension "pogo" when pedaling forces got high. about 18 or 19 miles per hour was top speed ( not sprint speed, but high effort cruise)

Back to the drawingboard. I cut down a rigid fork to 20 inches. This allowed a nearly straight chain line to a "30ish" degree idler right over the rear suspension pivot.

A few test rides show 20 to 21 miles per hour are possible to sustain on the flat.

NOW!!! Miles of practice and a tailbox should let me reach my 20 miles in an hour goal.

Update: November, 2002

I made a fiberglass seat. I wrapped the shaped seat base in plastic sheet and hand laid fiberglass ovet it. Then I cut up the wood seat and hand laid fiberglass over it. A frame of thinwall PVC pipe and another layer or two of glass finished it. It weighs a bit over 4 pounds. Kind of heavy, but, Hey!!!, we are amateurs. Total weight is now just under 40 pounds.

UPDATE March 30, 2003;

The 20 mph must have been with a tailwind or on adrenaline, subsequent rides showed 18 or 19 mph to be an average sustainable speed. The seat seemed to constrict breathing. Back to the drawing board

To check power line losses due to pogoing, I removed the shock and installed a bar in it’s place. Didn’t seem to make much difference.

I compared my seat to the Poweron Cycling seat. Mine was huge. I cut it up and eliminated the curve that made breathing hard.

Then I narrowed it to about 11 inches at the seat and 10 inches for the back. Test rides showed it bounced like a diving board, so I added ribs to give it a ThreeDee cross section.

Test rides showed a need for head/neck support, so I made a head rest out of PVC: I cut off a piece of PVC pipe, heated it in the oven, flattened it, reheated it and shaped it and, finally, made the last bend on the seat, using a heatgun.

I also bought a “real” 20” fork from Poweron Cycling. It was installed at this time. Trail checked out okay at ½ to ¾ inches. It was 1 lb. Lighter than my converted 559 mtb fork.

I also found a used 13-406 wheel. Mark says it is from a Lightening P38. It has a Sun aero rim and a Shimano Deore XT qr hub. I put a Shwalbe Stelvio 1 ¼ tire on it. This saved some weight, but I don’t know how much.

The total weight is down to 35 pounds. A couple pounds off the seat and one pound off the fork.

Here’s what it looks like.

I still have to build a tail box.