Errr,
Ron, it was a joke!
Just 'cos the tyre is flat at the bottom, it doesnt reduce the rolling
circumference.. I was pulling you leg!!
Actually, there is probably some differential calculus that coud calculate
the answer allowing for the "flat bit" which one could consider being made
up of an arc, or series of arcs, of different radii. But since the final
answer would be the same as your calculations for a proper round wheel, then
there wouldn't be much point to it!
Actually, there is another factor .... At high speeds (as in land speed
record speeds) the tyre will increase in diameter at high speed revolutions.
Anyway, did your parcel arrive?
Guy
----- Original Message -----
From "Ron Corry" <Corry at iol.ie>
To: "spridgets" <spridgets@autox.team.net>
Sent: Monday, December 15, 2003 1:42 PM
Subject: Re: Part ThreePointFive! of Tyre/Tire Diameters.
> Guy,
> You're correct, of course, but I think it's difficult to come up
> with a reliable allowance for that "flat bit at the
> bottom". These factors could include the pressure the tyre is inflated
> with, the load in, (and of), the vehicle
> itself, and the variable of how much stiffness the maker builds into the
> tyre walls.
> If there is a formula to take account of the above, (and possibly
> other factors like height above sea level)),
> I'd be delighted to hear of it.
> It strikes me that having arrived at the unloaded diameters, one
> would have to take actual measurements
> when the wheels is on the car, (from the hub centre down to the ground) in
> order to make a comparison. However,
> at that point, you would, most likely, have already bought the new tyres!
> My calculations, at least, allows one to make an informed
decision
> on paper, before purchase.
>
> Best regards,
>
> Ron.
> ===>
> At 08:49 15/12/2003, Guy Weller wrote:
> >Ron,
> >you haven't factored in an allowance for the flat bit at the bottom of
the
> >tyre. It reduces the radius.
> >Guy
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