since Daimler still owns 19% of Chrysler
I guessed about what thread to put this in

http://benzinsider.com/2008/02/c-cla...reduced-by-12/

sample quote:

Rolling resistance is primarily caused by tyre deformation as the tyre contacts
the road surface. This has a braking effect on the car, since additional energy is required to overcome this deformation resistance - therefore, the higher the rolling resistance, the higher the fuel consumption. Up to around 100 km/h, rolling resistance has a greater effect on fuel consumption than aerodynamic drag. The belt of this newly developed tyre for the C-Class contains a multi-layered mesh of high-strength steel for less deformation. It is also lighter in weight than conventional designs, enabling a further 1.7 kilograms or so to be saved per set of tyres. The secret, however, mainly lies in the chemical composition: the rubber compound for the treads and side walls is designed to ensure that rolling resistance is reduced by 17 per cent, while retaining the same good handling and braking characteristics.....Aerodynamic fine-tuning: Cd figure an outstanding 0.25_ At 120 km/h, the aerodynamic dragof the vehicle body already accounts foraround 50 per cent of all the dynamic resistance a passenger car must overcome. Accordingly Mercedes-Benz has been very active in the field of aerodynamics for many years, and has achieved remarkable advances that have had a positive impact on the fuel consumption figures of cars bearing the Mercedes star. With a drag coefficient (Cd figure) of 0.27, the C-Class is among the most aerodynamically efficient notchback saloons in its market segment. This is the result of a whole series of intelligent details, such as the tail lights with ventilation slits: these reduce drag by influencing the airflow along the side walls, causing it to break off at the tail lights without causing turbulences behind the vehicle’s rear end. In this way the patented tail lights of the C-Class replace the usual spoiler lips.