Traction and Tractive Effort
The force available at the contact between the drive wheel tyres and road is known as ‘tractive effort’. The ability of the drive wheels to transmit this effort without slipping is known as ‘traction’. Hence usable tractive effort never exceeds traction. The tractive effort relate to engine power as follows.
When the tractive effort F>R, the total resistance on level road, the surplus tractive effort is utilized for acceleration, hill climbing and draw-bar pull.