The formula to calculate the speed of the driven sprocket is:

\[ N_n = \frac{N_r \cdot T_r}{T_n} \]

Where:

• \(N_r\) is the speed of the driver sprocket in rpm.
• \(N_n\) is the speed of the driven sprocket in rpm.
• \(T_r\) is the number of teeth of the driver sprocket.
• \(T_n\) is the number of teeth of the driven sprocket.