DaimlerChrysler's engineers rewrote the rule books and developed a completely new type of wheel with two different diameters. The inside rim, which is most in contact with the road when cornering, measures 17-inches, while the outside rim is 19-inches in diameter. The best of both worlds system provides superb straight line stability while offering a much larger contact patch when needed most, in the curves. Interestingly some motorcycle racers have used a 'V' shaped tire to improve the contact patch during high-speed cornering, similarly maximizing the contact patch when leaning the tire. The F400 Carving's tires measure 255/35R19 at their outer edges and 255/45R17 on the inside rim.
The concept's drive-by-wire braking performance is also enhanced due to the steering technology. During an emergency stop, each wheel can be immediately canted to shorten the car's stopping distance from 100 km/h by five meters (16.4 ft) over conventional braking systems. The fact that carbon-fibre-reinforced ceramic 330 mm (13.0 in) diameter rotors are used doesn't negatively affect stopping power either. But no matter how large they'd have little effect in standing water, where traditional tires, especially wider, low-profile rubber that is biased for performance, hydroplane. The active camber control system takes care of this problem too however, by adjusting the tire's contact patch a few degrees to compensate. This works in tandem with a new sensor that detects water layers on the road surface, measures and sends the information to car's ECU, resulting in an immediate camber change to stabilize the vehicle.
But, being a research car, the Mercedes engineers didn't stop with the F400's active camber control system. Additionally, steer-by-wire technology has been integrated, removing the need of a potentially dangerous steering column while enhancing directional precision. The system incorporates sensors that respond to the driver's steering wheel input and then transmit the information to twin microcomputers that, in turn, produce commands to control the electrically actuated steering gear.