>Why not make your own fifth wheel? As you wrote, you can roll it 100
>rotations and
>get the accurate distance. Here is how I would do it: first, make a frame that
>attaches to the car, then a fork with a pivot and a bicycle wheel, a hatch
>strut
>to give it an even pressure to the ground, and a bicycle speedometer. These
>speedos can be programmed to fit the circumference of the wheel, by the exact
>millimeter. The only drawback is that you would have to mount it close to the
>driver or passenger seat, because the bike speedos don't have too much wire.

If you wanna go to this much trouble, surely lengthening the cable wouldn't
be too much trouble? They're just two wires in a heavy duty sheath to
prevent abrasion.

Joshua Van Tol -- jjvantol@lear.csp.ee.memphis.edu