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).