Report No. 2

 

A simple experiment may carried out to determine a vehicles final drive ratio and the gearbox ratios.

Procedures:

1.     Chock the front wheels and jack up one of the rear wheels (in case of rear drive axle), mark tire and floor surface.

 

2.     Select top gear. Rotate the rear wheel exactly two revolutions. Not number of revolutions made by the crankshaft.

 

Final drive ratio (i_f) = number of turns of crankshaft

 

3.     Select and engage first gear and repeat above procedure (2) and again note exact revolutions of crankshaft.

Since the overall reduction ratio = i_g x i_f .

Therefore 1st. gear ratio i_g1 = (number of crankshaft revolution per 2 wheel revs.)/ final drive ratio.

 

4.     Repeat procedure for the other gears.

 

Note: When one wheel is raised off the road surface, and a standard type differential is fitted, the raised wheel will make double the normal number of revolutions.