One thing I've noticed it that Tire Rack shows very different R/Mile
than

http://www.miata.net/garage/tirecalc.html

http://www.tirerack.com/tires/Spec.jsp?make=Sumitomo&model=HTR%
2B&tirePageLocQty=

205/55VR16

811

vs...

848

On Nov 17, 2007, at 11:52 AM, John Bange wrote:

> here are 63360
> inches per mile, 60 minutes per hour, so (conveniently)  60mph = 63360
> inches/minute. 63360 divided by 81 gives you 782 wheel RPM, which
> multiplied
> times 4.09 for the differential gives you about 3200RPM ideally.
> Torque
> converter slippage will trend that a little higher, how much being
> determined by headwinds, hills, air resistance which increases at
> higher
> speeds, etc., but 10% makes a good high end guess, so divide by .9
> for 3555
> RPM. That means you should be indicating 3200-3500 RPM at 60mph.