The drivetrain of a commercial vehicle forms a mechanical, torsional vibration system. Sudden changes of the torque can give rise to large vibrations, especially when accelerating from rest. Determination of peak moments is critical for correct dimensioning of transmission and drivetrain components.A theory has been developed which permits sufficiently accurate simulation of the start-up vibrations in the drivetrain. The paper subdivides the system into its smaller components (clutch, drive shaft, tires, etc.) and then applies the equation of motion to the components. Theoretical results are compared to test measurements and the regions of theoretical validity are determined. Results are then described for the individual drivetrain components. Emphasis is placed on the distinction between the factors with greater and lesser importance for the peak drivetrain moment.