A new approach has been used to perform detailed molecular dynamics simulations for several cyanobiphenyl liquid crystals. The molecular potential is obtained by considering the phenyl rings in the liquid crystal molecules as enlarged spherical extended atoms. This method allows more rapid simulations than those using full atom-atom potentials, without losing any structural or orientational information. To investigate the nematic properties of the cyanobiphenyl liquid crystals, we calculated the order parameters for the principle molecular axes, C-H bonds in the alkyl chains, and C-C bonds of the alkyl chains of four cyanobiphenyls, and compared the results with available experimental data. Diffusion coefficients in directions both parallel and perpendicular to the director have also been calculated. To study the conformational equilibria of the model systems, we have also calculated dihedral distribution functions for several of the relevant torsional angles.