Another fun calculation that can be done is the total tractive effort at the tires, where Total tractive effort at tires= ( tractive effort at engine(torque) X transmission ratio X final drive ratio / tire radius in ft) X drive line efficiency.
So if an engine makes a max of 400 ft/lbs of tq than in 1st gear (2.87) with a final drive ratio of 2.73 divided by tire radius 11.93/12 in ft X drive line efficiency say .85
The total ft/lbs at the tire = (400 X 2.87 X 2.73 /11.93/12) X .85 = 2,691ft/lbs at the wheels, if the final drive is changed to 3.11 than (400 X 2.87 X 3.11 / 11.93/12) .85 = 3,066.
So, when the final drive was changed to 2.73 allowing more top speed the tire tq in 1st gear went from 3,066 to 2,691 ft/lbs. The max tire tq effort can be calculated for each gear.
|