On Mon, 25 Jun 2018 18:02:49 +0100, The Natural Philosopher
wrote:

On 24/06/18 08:03, Richard wrote:
On 23/06/18 17:01, The Natural Philosopher wrote:

No.
Since no wheel is circular using radious as a concept is plain wrong.
At best you can calcualate a '*radius it would be if it were round*,'
from the actual circumference.

The use of radius is completely right.
The circumference doesn't change. The centre of the instantaneous circle
moves closer to the radius.
The tyre is a three dimensional structure and this debate is being
conducted in a two dimensional manner.


I hope no one ebver emp;loys you in an engineering capacity.

The use of radius is meaningless. The the tyre is not round.

That's why 'most people' that know what they are talking about use the
terms 'rolling radius' (effective loaded radius) and have done for
years, and all without your understanding or permission!

From this dynamic value you can extrapolate the rolling circumference
or even measure it (as it's a real thing of course).

Plug an OBD reader into your ABS equipped car and pickup one of the
sensor ring outputs.

Measure the unloaded circumference of the tyre.

Use the output of the ABS ring to count the wheel revs, calculate the
theoretical distance traveled and compare that with a GPS or road
marked value. Report back here with your findings. ;-)

Cheers, T i m