|
say your tires are sized 225-65-16
sidewall height = 225 * .65 = 146.25 mm
top and bottom sidewall = 2 * 146.25 = 292.5 mm
both sidewalls in inches = 292.5 * 25.4 = 11.52 in
total tire diameter = 11.52 + 16 (rim) = 27.52 in
tire radius (ft) = 3.14 * 27.52 / 12 = 7.2 ft
revs / mile = 5280 / 7.2 = 733.33
rpm is more useful for mpg than revs/mile.
rpm @ 60 mph = 733.33 * top gear ratio * final drive
__________________
11-mile commute: 100 mpg - - - Tank: 90.2 mpg / 1191 miles
|