Traction of tractive efficiency is a function of which two factors?

• A. Engine horsepower and transmission ratio
• B. The weight on the equipment's drive axle and the surface on which it is gripping
• C. The tire material and tread depth
• D. The color of the machinery

Answer: (B)

Traction is governed by the interaction at the tire–surface contact. The maximum grip you can transmit before slipping depends on two main things: the load on the drive axle, which provides the normal force, and the surface itself, which determines how much friction (the coefficient of friction) is available. More weight on the drive axle increases the normal force, boosting the frictional limit, while a rough, dry surface offers more friction than a wet, icy, or loose surface. In simple terms, the tractive effort you can use is about μ × N, so the two factors are the weight on the drive axle and the surface characteristics. Engine power or gear ratios matter for how much power could be transmitted, but actual traction is set by this frictional limit.