Given:
MPH = 60
Axle Ratio = 3.90
Trans Ratio = 1.00 (3 speed standard)
Tire circumference = 90.25" (converts to tire diameter = 28.72747" - rounded to nearest thousandth to 28.728" for entering into RPM calculator)
RPM = 2737 (rounded to nearest whole number)
(See screenshots below for "the math" - lol
)
See also resource aid
Calculate RPM... found on the main
Tech Tips page 
Dan
