[python] Re: lean steer trike

Hillel,

Judging from the size of the cranks, I'd guess the tube size is 1 1/2 inch and by the stated weight of 36 pounds using 4130 chromoly I imagine Bob used .065 wall diameter tubing. 4130 x .065 weighs .9962 per linear foot. One would have to experiment and see what the optium tube size versus stiffness would be. It's really difficult to tell much from the limited views he provides.

In Bob's trike the front section is part of the seat frame.
What size pipe does it look like? I don't know if the Python design requires a little more vertical stiffness. I don't think it should matter if the welds are good.

I think Juergen made reference a few days ago to the angle of the sterring pivot having a lot do with the overall handling characterisitcs. As I recall, he said the angle was 80 degrees.



Another thought is that the original design using bar stock
is forced to set the steering pivot (BB) at an angle that is
perpendicular to the bars going forward for the front section.
If you use a rectangle from round pipe as the front section,
then the BB used for the steering pivot can be at any angle,
even less vertical like the flevo-bike, and the pedals can
still be wherever you want them.

---Hillel

On another note...

I built a trailer that I pull behind one of my bikes a few weeks ago, which in principal pivots much like a center steer bike. I just slammed it together in about an hour without giving much thought to the angle of the pivot. Fortunately, it worked out very well. I don't think I'd want to use it for touring, but it works great for hauling things around town. So far, the heavest load I've put on it is a little over 100 pounds.

The reason I bring this up is beacuse My cash outlay for the trailer was $0 (I used completely recycled metal parts), it required NO welding which for some builders is a big plus and I built it in less than one hour.

If anyone is interested in I'll take some mearsurement, and make some sketches. I might even take a pic or two if Santa remembers that I was a good boy this year and want a digital camera. :-)

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