The Story of Our Recumbent Tandem Bicycle:

Path, The Green Dragon

by Gary Dinsmore

Getting Started:

Brazing the Frame

Sometime in late 1999 I finally finished doodling in my notebook and actually started creating a recumbent tandem bicycle. I called it the Double Dinsey. Very slowly over the next few months the several sub assemblies were cut out, mitered and brazed together. It was finally assembled into a complete bicycle in March of 2000. I have a photo of myself riding the Double Dinsey solo on March 21, 2000. In the ensuing weeks we tried to learn to ride the bicycle together. Except for some very short coasting experiments we were never able to successfully ride the new bicycle as a tandem couple.

Frame Mockup

Gary Rides Solo

Reworking:

I went back to the drawing board and after several months and some very serious study of Dr. Bill Patterson’s book, “The Chronicles of the Lords of the Chainring,” I redesigned and rebuilt the Double Dinsey as the Mark II model. The principle change was to lengthen the frame about four inches and increase the head tube angle from 65 degrees to 74 degrees. At the same time the cantilever suspension assemblies were given a brace at the position of the seat stay. This forced the two arms to swing as one so the wheel would track straight.

First Ride:

The Mark II model was complete except for painting in February of 2002. We waited for a couple weeks for perfect weather and finally on February 14, 2002 we made our début ride on the new tandem. It was a 23 kilometer ride around the dike road loop near our Scappoose home. We rode the bicycle naked. I mean the bicycle was naked of course, not us. We had to prove that the Mark II model was completely to our liking and didn’t have any bad handling habits. It passed with flying colors even without paint and I proceeded to disassemble the frame back to its smallest components. The frame components were taken to Class Act Paint in Portland and were painted a flashy metallic flecked green. We retrieved the painted components on April 1 2002.

Boise Idaho, May 2002

Eugene Oregon, July 2003

Path Tries His Wings:

It took until after my 60th birthday to get the Double Dinsey, Mark II completely assembled and tuned up for riding. On April 27, 2002 we celebrated with a 45 kilometer ride around the dike and into St. Helens and back. We hadn’t settled on a name for our new bicycle at that time, and my records show the tentative name of the Green Lizard. Judy found a Beanie Baby dragon and this became our mascot. As time went on this bicycle became known as Path, the Green Dragon, based on the Green Dragon of the same name in Ann McCaffery’s Dragon Riders of Pern series.

Path’s first official outing was the Ride the Ride, Ride with our local BTA group in preparation for a Riverfest ride that our group sponsored. On that ride we bent the steering tube and had to have some friends sag us home. The front springs were too limber and this allowed the tire to contact the bottom of the steering tube and stop abruptly. This sudden stop over stressed the steering tube. The Fox RX Vanilla shock was upgraded to an 800 pound spring. This helped, but the head tube has been rebuilt several times, and we have learned to take curb cuts with caution.

Our first official portrait of Path came at the Northwest Tandem Rally over the Memorial Day Weekend 2002, at Boise Idaho. This is the photo that we hand out on our calling card. At this time I was using flat mountain bike style handlebars. This is sometimes called the “begging hamster” position. By the time the tandem rally came around in Eugene, Oregon in 2003, I had changed to the “drooping handlebar mustache” style that we are currently using. If you look carefully at the 2003 photo you can see the tail cone fairing that we used to try to overcome the wind resistance of our upright position. We never followed through with plans for a complete body sock. The only time we regret this is when we are fighting our way into the teeth of a strong wind. Even the tail cone went away when we condensed our home into a 34 foot motor home.

Here are some of the details of the bicycle:

The wheelbase is a fairly short 50 inches.
The seats are by Rans and they are fairly upright. They weigh 6 lbs each
The captain’s position is a swinging-feet style front wheel drive.
	Seat height is 31 inches at rest and compresses to 30 inches when seated. Bottom Bracket is 21 inches
The stoker powers the rear wheel.
	Seat height is 29 inches at rest and 28 inches seated. Bottom Bracket is 16 inches Stoker’s seat is cantilevered behind the rear suspension.
Each person has a full set of derailleurs and completely independent cadence.
	Cranks are Shimano RSX road components. Pedals are SPD clip-less Captain has 52-45-36 chain rings. (Limited by an error in the front derailleur angle.) Stoker has 58-45-36 chain rings.
The suspension for both wheels is identical trailing arm cantilevered forks.
	Pivot is a 3/8 stainless steel bolt with ball bearings. They are sprung with Fox RX Vanilla, coil spring and oil damped suspension. Captain’s position uses an 800 lb spring. Stoker’s position uses the stock 700 lb spring.
The wheels are 20 inch 406 Veluta, Airline1, wheels, laced semi-radial.
	Shimano Deore LX Free Hubs with Nexave, Megarange derailleurs. Shimano Hyper Glide, 32-11 cassettes Tires are 1.5 inch semi-slicks running 100 PSI. The brakes are Magura hydraulic.
Captain has a 95 gear inch drive train and stoker has a 105 gear inch drive. This limits the top speed to about 44 kilometers per hour. Minimum speed that we can maintain balance is about 7 kilometers per hour. This represents a cadence of about 70 with the 22.5 gear inch granny gears.
Initially Rapid Fire shifters were used. I changed to bar end shifters in friction mode. Construction is fillet brazed 4031 chrome-molly aircraft tubing. Some of the critical joints are lugged.
Weight ready to ride with lights etc. is 67 pounds.

Return to "Travel Blog Home Page."