On Oct 14, 2011, at 11:39 AM, Rob wrote:

> At  10/14/2011 06:41 AM, Robert Mac Dowell wrote:
>> Let me rephrase that. How many RPM'S should it be for the speedo to be right
> 
> I've been using http://www.1010tires.com/tiresizecalculator.asp to
> see sizes, revs & all that stuff for different sized tires.

For whatever it's worth in this discussion:

Tire Rack stated rpm's for my tires= 715
10/10 calculator= 718.4
Miata.com calculator= 697

bob
BFG A/T KO 235/70-16's
http://www.flickr.com/photos/syncronaut/6180809162/in/set-72157615490910502