[Spridgets] calculating speed

[Weslake1330 at aol.com]

So sothe tyre manufacturers account for this when they give you a wrpm  
figure?
 
In a message dated 19/10/2008 04:30:42 GMT Daylight Time,  
dlh2001 at comcast.net writes:

I  disagree.  A tire does grow in diameter as a function of the square of  
its rotational speed.
The steel belt limits this, but not as much as you  think.  Basically the 
sidewalls move inward
and the center of the  tread goes outward.

The growth is not much, but it is enough to impact  the final drive/rpm 
calculation.

Tire Growth Factor = 0.000100  (Inches/(MPH*MPH)) 

so for 50 mph  0.0001(50*50) = 1/4 inch  increase in diameter.

The above formula is probably generic, different  tires probably behave a 
little different, 
but they will all grow with the  square of the rpms.