A SIMPLE method of predicting truck performance in terms of grade ability at a given road speed, taking into consideration rolling resistance, air resistance, and chassis friction is presented here.
A brief review of fundamental considerations is given first, then the method recommended for predicting vehicle ability at a selected speed, and finally a few words on the prediction of maximum possible road speed and selection of gear ratios.
The basis of the solution is the determination and expression of vehicle resistances in terms of horsepower - that is, in terms of forces acting at a velocity.
A convenient method of solving the grade problem at a given speed is by means of a tabular computation sheet, which is given, together with tables and charts. These assist in making the computation an easy one as well as giving the necessary data on vehicle resistances.