On the Tire Rack site, they list the specs for many different types and sizes. I just pick the correct tire and look up the revs per mile. The figure is calculated using the loaded radius. Multiply the revs per mile by the rearend ratio and you have the RPMs for 60 mph. To find the revs for another highway speed just scale thast figure.
Oh, on my truck I have installed the 410 gears. With my tires the rpm at 50 mph is just a little over 2000 and that is where I like to keep it.
Last edited by truckernix; 03/23/2009 1:55 PM.
