VERSION #1

The student team purchased, at a considerable discount, a Cannondale Lefty DLR bicycle and made several modifications to it. A unique feature of this Cannondale model is its "Lefty" fork that goes down only one side of the wheel. This arrangement allowed the students to put a sprocket on the other side of the front wheel over which they could run a chain that was also connected to a sprocket system mounted off the handlebars that in turn was linked to a crank and hand-pedal system that the rider could use. Another interesting feature of this initial version was the placing of the cranks in a parallel position, as opposed to the 180 offsets found in standard bicycle foot cranks.

This arrangement was necessary to enable riders to better steer the bicycle while pedaling with their hands. The student effort was a significant achievement and served to prove that such a bicycle could be built and ridden. (The students received an "A" grade in the course.)

Version #1 did have some problems that needed to be corrected in order to make it safe to ride long distances. The fork was placed on the right side of the wheel instead of the left side for which it was designed and this allowed the bolt that held the wheel in place to turn in the wrong (loosening) direction. The bicycle also had the front brake removed which not only reduced the overall braking power of the bicycle, it eliminated the back-up safety feature designed to hold the wheel in place should the front axle bolt fail for some reason.

VERSION #2

VERSION #3

Richard Reis, AIM executive director, rode Version #2 to and from Los Altos, California to Stanford University (about 12 miles round trip) most week days during the months of August - December, 2003 making minor modifications from time to time.

Good as Versions #1 and #2 were, they did not fully meet the goal of a "normal" bicycle that could be pedaled with the hands and the feet. The Cannondale was an expensive bicycle with a unique front fork arrangement not likely to be something a normal rider would want to acquire. In addition, the front end of the bicycle was quite heavy and this made steering somewhat difficult. (Note: The full bike weighed 75 pounds compared to a typical bicycle weight of 20-25 pounds.)

In January, 2004 Reis set about building on the Version #2 concept by modifying a standard, Specialized 26 inch 02 Crossroads Comfort Bike that was purchased from the Stanford Bike Shop for $200.00 After developing a number of prototypes and riding them to and from work, Reis settled on the one shown in Photo 2. The special features of this bicycle are listed below:

With the above arrangement it is possible to ride the bicycle in the normal way with the gearshifts and standard front and rear break grips on the standard handlebars. At any time riders can remove their hands from the standard handlebars and grip the hand pedals. They can hand coast in this position or hand pedal, whichever they choose. Braking is done with the left grip while in the hand pedal mode. Shifting and standard braking is done by returning the hands to the standard handlebars.

VERSION #4

While Version #3 worked well it still had some problems. The rotating hand brake on the left hand pedal was awkward and still required letting go of the right hand pedal in order to use the rear brake.

Version #4 solves these and a number of other minor problems. It was constructed by Reis from two new 26 inch Townie Electra bicycles as shown in Photo 4.

The Townie bicycle has a number of desirable features:

The rear wheel of Bike #1 replaced the front wheel of Bike #2, which became the final bike.

Making this change required the spreading the front fork of Bike #2 by about 0.75 inches. The coaster brake of this now front wheel was attached to the fork and the gear-shift for the front hub was mounted on the left handlebar. The rear triangular frame of Bike #1 was cut and mounted on the handlebars of Bike #2 in a manner similar to that of Version #3. The hand-pedals were aligned in the same way as were the guide sprockets.

This arrangement allowed riders to brake with both their feet and hands without removing either from their rotating positions. Simply by pushing forward on the hand-pedals when in their lower position riders can easily slow down the front wheel while maintaining full control of the steering.

Not only can riders shift the rear wheel to one of three gears, they can do the same with the front hand pedaled wheel giving even more control while pedaling and steering.

VERSION #5

One difficulty with Version #4 was that the triangle frame piece attached to the handlebars extended much too far in front of the bike making it hard to control when turning. The length of this unit was dictated by the fact that it was cut from the rear of Bike #1 and was never designed to extend out in front of the new bike. A significant portion of the frame was cut off and the pulleys were mounted closer to the handlebars. (See Photo 6). Note that the pulleys could not be brought too close the handlebars otherwise the chain wouldn't clear the front fork and a rider would not be able to make a sharp right turn.

Also note the cool windshield, the red lights on the valve stems and the Sissy Bar. Now all we need are the plastic streamers that extend out from the handlebar grips.

VERSION #6

A problem with Versions 1-5 is that the hand crank support tube is mounted off-axis in front of the neck of the fork. A more ideal position would be an extension along the neck axis itself and this is the case in Version #6. (See Photos 7 and 8). Not only does this arrangement provide a cleaner look, it is lighter due to the absence of mounting gear, while providing a more natural and balanced steering system. In Version #6 the rear toolbox has been replaced by a Zuca Bag ( http://www.zuca.com/) that can be easily detached from the carrier for transport.

VERSION #7

In Version #7 a decision was made to return to the two-chain option. In this approach each chain is shorter and as such has a smaller vibration amplitude and is thus more stable with respoect to the chain sprockets.

VERSION #8

Version #8 is an entirely new bicycle, but one clearly modeled on the previous version.  In Version #7 a number of "mistake" holes had been drilled in the frame (and covered with black tape) and this made me nervous.  The hub at the front support was taken directly from the rear of a discarded 12- speed bicycle and had many more sprockets - and weight - than needed. I also thought it was time to "clean up" the design and bit, to make it look less cut-and-paste and more like something that would come out of the same factory that made the original Townies.

I started with two identical three-speed Townie Electra's, just as in Version #7, except that the new ones were red.  See photo 11.

I replaced the front wheel of the first (final) bike with the rear wheel of the second bike and started cutting up the second frame as before. See photo 12.

I decided to use the entire rear triangular frame of the first bike just as in Version #4.  This guaranteed that the hand pedaled sprocket

would line up exactly with one of the sprockets in the front hub.  It also provided a factory-designed support for the front hub. Because, unlike Version # 4, the mounting took place on top of the neck, the extension out over the front wheel was not as great. This new arrangement  did create an undesirably high moment of inertia when steering.  This was reduced considerably by mounting the heavy bicycle light battery to the rear of the stem axis, providing a counterweight that makes steering quite easy.

Since the overall weight of the bicycle remained the same there was no real downside to such a move.

I replaced the full sprocket front hub with one that allows one or more sprockets to be replaced by spacers.  Thus, I only had to use two sprockets. A number of other touches went into giving the bike a more polished look. 

I replaced the toy Honda rev-and-roar motor with a custom Townie bag from Electra.  I purchased a backrest designed for children's bikes and mounted it in front of the Zuca bag from Version #7.  It is much more comfortable. 

Finally, I ordered Fullbodybicycle.com signs for mounting on the sides of the Zuca bag.

VERSION # 9

One problem with Version 8 is that the horizontal hand crank support is quite long.  This is of course the way it comes from the bottom of the supply bike but it results in a large moment of inertia when turning  and this makes steering less than ideal.  I tried compensating for this to some degree by putting counter weights near the crank but clearly a better solution would be to shorten the moment arm and this is what I did in Version 9.

I started by having a thick aluminum plate welded across the support bars as shown in Photo 16 and then cut off a portion of the support bar as shown in Photo 17.  The welded plate width was designed to fit snugly into the bottom of what is normally the kick-stand support located closer to the cranks.  I then secured the plate with three bolts and remounted the unit back on the bicycle as shown in Photo 18.

Shortening the horizontal arm required some minor realignment of the chain sprocket guides at the front wheel as shown in Photo 19.

Photo 20 shows the final current version.  It does indeed steer much more easily than Version 8.

If you have any questions or comments please contact me at: reis@stanford.edu