Hi Bob

 BL> The axle rotation (and hence speedo reading) is basically the
 BL> linear movement on the ground divided by the axle height.

 BL> This is just simple maths.

 RM> This is the linchpin of your argument, and it's got a huge hole
 RM> in it: it's true only for a circle!! For the umpteenth time, a
 RM> flattish tyre is NOT a circle. The axle is locked to the tyre,
 RM> *not* to a circle.

 BL>  It has nothing whatever to do with circles. Do you understand
 BL> calculus? Even vaguely?

Yes. I understand it clearly enough to see the faulty assumptions
you've made applying it. d0/dt is nice and steady right round for a
circle, but varies like mad across the distorted shapes we're
talking about. Your approach is grossly oversimplified.

 BL>  I don't want to be rude Roy,

That makes a change.

 BL> but this is INARGUABLE. I understand
 BL> that you don't think so, but when you roll a wheel connected to an
 BL> axle, the axle rotates as I say: linear movement on the ground divided
 BL> by axle height. It can't be anything else.

Of course it can. You haven't read what I've said at all. Take a
rigid rim, give it an axle with elastic spokes. Push the axle down
5%, turn the wheel. The axle must rotate at the same speed as if it
was still at the centre, because one rev of the wheel still carries
the axle one circumference forward. If the axle rotated faster, the
spokes would wind up around it.

Don't just say "this is INARGUABLE", tell me what is wrong with the
above para.

 BV> The thing that is rolling
 BL> can be *any* shape... a bloody great long flat thing, a perfect circle
 BL> with point contract, or even a coil that squirms sideways like a
 BL> snake. It's just the way it is... basic maths taught in High School.

So if we make a rubber wheel with a tiny hub that otherwise behaves
the same as a car wheel, and squash it down until its axle is 99%
closer to the ground, we end up with an axle rotating 100 times
faster. This means the top of the tyre is going forwards above the
axle 100 times faster than the bottom of the tyre is going
backwards below it.

This is obviously impossible, but it fits your "theory" exactly. If
your understanding of this is so clear, explain what is wrong here.


Cheers

--- PPoint 1.88