Tuesday, October 2, 2007

Imagining Bikes - Biking Minnesota

It has been stated that to try and forecast the weather in Minnesota due to three climate systems coming together in the middle of the state is like a crap shoot. Now, throw in the effects of climate shift and, boy-oh-boy, it is any one's guess. My Dad, who was a meteorologist, used to be able to predict locally based upon the lay of the land when they lived in southern Georgia. I think this place would have challenged him greatly.
Working outside in the Western U.S. for around four to five years, frequently in the middle of nowhere, forced me to carry three sets of clothes and two sets of foot ware along with other necessary survival gear for any type of weather conditions, plus a sleeping bag. One even stashed emergency rations anywhere and everywhere.
Your experiences should teach you to plan for overcoming the last miserable challenge and your survival may depend upon being able to effectively imagine the possibilities. One hopefully learns to overcome the circumstances and learns to use the past similar to tools in the toolbox. Of course, one can't afford to lug around all fixes to all possibilities so one must melt it all down to the smallest possible denominator - what can one afford to carry with one's self? What will it cost in weight? How does it perform in the worst conditions of cold, wet, dark and muddy? And, if your tools fail you or can't do the job with those tools? What if the whole thing is out of commission? Can you effectively carry it or push it?
I rode for years in all types of situations, mostly on the safety. Then, I learned on both the long wheeled base recumbent after an experience on a short wheeled base recumbent. Before those times, I had the situation of having to ride a tadpole trike both with, and without, a front fairing through winters.
There are drawbacks to every available model out there, but none that can't be overcome. Just like life.
I would like to take this time and space to acknowledge a friend who built many of the recumbent bikes and trikes I've ridden over the years and who has been a mentor, employer and business partner, Dave Krafft. It was while working with Dave on his housing makeover that we fixed his long wheel based single tube recumbent model after the tubing we had bought had failed due to the thin walled material. He was going to cut the failed part out and braze a thicker walled tube into the frame when I stopped him and proposed an alternative. (Here is where the oilfield experiences kicked in.) I told him to just put a steel cable between the front crank and the rear crank housing with a turnbuckle, and take the stress off of the tube. A trip to the hardware store, a little metal fab and it was ready for service.
We didn't just end up fixing a collapsed tube. Four prototypes readily proved we had found a solution to the dilemma of frame flex robbing power to the drive train and a host of other problems such as pogoing for that model frame and controlling frame flexure along vertical and horizontal lines without adding member framing, i.e. weight. With the long wheel based (LWB) single tube model, my feeling was that the frame became the suspension. We had to repair the hardware parts many times until we upgraded to better fixtures and cables, plus we learned we had to run the cables all the way to the back to be more effective.
Since those days, both studying why these things worked and other people's art/science of structure, I've come away with more understanding and have built a model applying these same principles to the upright, or safety bike. It works the same as far as I can tell. The biggest kick comes from understanding that the frame can be "tuned" to fit the riders weight at the time. Want a cushier ride, just loosen the frame up.
On a test ride for our first redone prototype, I alarmed Dave when I took these horrendous railroad tracks crossing the street full bore. I mean, these holes around the tracks could flatten your tire and twist your frame into a pretzel! But, nary a thing happened. I didn't even get thrown off of the bike. The bike ran true. The same for hitting sand on the trail. You just aim the bike and power through it.
Now that I've read Buckminster Fuller and viewed the work of Kenneth Snelsen, I find it completely remarkable that no one has understood basic physics when it can be applied to the problem of frame flexure for bikes or other structures. It is all about force vectoring. There was another gentleman that pioneered "tortured plywood" in building catamarans on the West Coast back in the Fifties. I think "Pile" was his name? It's the same principle. You build in, or apply force which can't be overcome by the motion which gives you the problem to begin with. Of course, one has to make sure that the structural member has enough strength range to endure the problems it will face later on through use.
Imagine an upside down bow. The connecting tubes between the front wheels and the rear wheels(axle) are now held in tension with the rider sitting on the top of the compressive member. The more movement vertically results in more compression which results in tension. As the tube at static has very little bend, it is just seeking to return to its' normal condition. The rider's weight(gravity) is counteracting the bending moment of applied tension. Place an adjustable connecting member underneath the rider, and now you have two triangles between two wheels, which give ever so slightly. I refer to it as using the frame for the suspension system.

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