This paper presents a six degree of freedom full vehicle model simulating the testing of heavy truck suspensions to evaluate the ride comfort and stability using actual characteristics of gas charged single tube shock absorbers. The model is developed using one of the commercial multi-body dynamics software packages, ADAMS. The model incorporates all sources of compliance: stiffness and damping with linear and non-linear characteristics. The front and the rear springs and dampers representing the suspension system were attached between the axles and the vehicle body. The front and the rear axles were attached to a wheel spindle assembly, which in turn was attached to the irregular drum wheel, simulating the road profile irregularities. As a result of the drum rotation, sudden vertical movements were induced in the vehicle suspension, due to the bumps and rebounds, thus simulating the road profile. Experimental testing of a gas charged single tube shock absorbers was carried out using an MTS damper tester. The experimental characteristics of two modes were fitted and performed. The results showed that in smooth, flat roads, using the gas charged single tube shock absorber in soft mode improve the ride performance by 58% compared to the hard mode at different speeds. On the other hand, for rough roads, using the gas charged single tube shock absorber in the hard mode was shown to improve the ride performance by 27% and the stability in terms of the pitch angle by 33% compared to the soft mode for the same road profile.