The design of heavy trucks with respect to the ride comfort poses two classical problems. One is the articulated vehicle problem and the other is the “jumping ride” problem caused by elastic vibrations of the frame. The two problems have been identified in field investigations. The vibration isolating system of a truck has been analysed by means of mathematical simulation. Mathematical models of different sizes have been used to examine the influence of different parameters. The damping, cab suspension and frame vibration are discussed in detail. Efforts to optimize the system have been made. These results and the results from measurements, such as impedance tests and road tests, have been applied in the development of a COE heavy truck family. The final judgement of the ride comfort of these trucks is also presented.