Wheel Slip ($W_s$):

$$W_s = \left( \frac{N_o - N_l}{N_o} \right) \times 100$$

Where:

• $W_s$ is the wheel slip, in percentage (%).
• $N_o$ is the sum of the revolutions of the driving wheel without load, in revolutions (rev).
• $N_l$ is the sum of the revolutions of all driving wheels with load, in revolutions (rev).