Duane
IH8MUD Wookie
This is like one of those bonus math questions at the end of the test.
I assume the number you want to know is your differential gear ratio?
But as the question you asked, "what is my gearing" then this should be simple. 2500 rpm X 60 = 150,000 rph / 70 mph = 2142.8571 engine revolutions/mile. Assuming that you have a factory 31inch tire then the circumference would be Pi x d = 31 x 3.14 = 97.34 inches. 1 mile - (5280 feet x 12) = 63360 inches. Therefore tire revolutions / mile would be 63360 / 97.34 = 650.91432 revs/mile. Now we get to our "gearing ratio" as requested 2142.8571/650.91432 = 3.2920720 : 1
( I should have used more decimal places in Pi(3.14...)
I would assume that your 5th gear transmission ratio is not 1:1 It likely offers up an over drive scenario where the output shaft is turning slightly faster than the input shaft.
Short of counting teeth, maybe drop your rear u joint, jack up the rear of the vehicle mark tires and the pinion and check it out.
I assume the number you want to know is your differential gear ratio?
But as the question you asked, "what is my gearing" then this should be simple. 2500 rpm X 60 = 150,000 rph / 70 mph = 2142.8571 engine revolutions/mile. Assuming that you have a factory 31inch tire then the circumference would be Pi x d = 31 x 3.14 = 97.34 inches. 1 mile - (5280 feet x 12) = 63360 inches. Therefore tire revolutions / mile would be 63360 / 97.34 = 650.91432 revs/mile. Now we get to our "gearing ratio" as requested 2142.8571/650.91432 = 3.2920720 : 1
( I should have used more decimal places in Pi(3.14...)
I would assume that your 5th gear transmission ratio is not 1:1 It likely offers up an over drive scenario where the output shaft is turning slightly faster than the input shaft.
Short of counting teeth, maybe drop your rear u joint, jack up the rear of the vehicle mark tires and the pinion and check it out.
