Steer-by-wire becomes reality at Mercedes-Benz.

A new era of vehicle operation is about to begin for Mercedes Benz customers – the company will be the first German car manufacturer to offer a production vehicle with steer-by-wire from 2026. This technology does not require a mechanical connection between the steering wheel and the front wheels. Instead, the driver's steering requests are transmitted quickly and directly via an electrical cable, i.e. “by wire”.

The completely new steering feel provides an unparalleled customer experience with a wide range of advantages in everyday driving: handling is better and manoeuvring and parking become even easier. This is because steer-by-wire can further reduce the effort required and there is no longer a need to re-grip the steering wheel while parking.

The suspension specialists can choose the steering ratio variably and adapt it flexibly to different situations. This enables the simultaneous optimisation of driving characteristics that were previously in conflict with one another. Likewise, it can bring further increases in directional stability and lateral agility, which is also thanks to the perfect interaction with the rear-axle steering (with a steering angle of up to 10 degrees). Vibrations caused by uneven road surfaces, which were previously transmitted to the driver via the steering wheel as disturbances, can now be almost completely prevented.

The potential for individualisation is high through adaptation of the electronic steering to customer preferences. Individual brands or certain models within a series can be given different steering characteristics. Steer-by-wire also creates new potential in the design of new architectures by decoupling the steering wheel and steering gear. An additional future potential benefit of the technology is the opportunity for immersive gaming when the driver stops for a break.

The steering wheel can be flatter, which results in a more spacious feel and a better view of the driver's display. It also makes getting in and out of the car easier because the flattened underside of the steering wheel creates more room. In combination with future conditionally and highly automated driving systems, the driver could have a new, even more relaxed position in the long term.

The functionality of steer-by-wire in detail: depending on the driving speed and situation, an actuator on the steering wheel (steering feedback unit; SFU) sends the driver's steering signal to the steering rack (steering rack unit; SRU), which steers the wheels. The SFU also generates the steering feel typical of Mercedes Benz. Since the mechanical decoupling of the steering wheel and wheels eliminates steering torque, the tyre-road contact is calculated on a model-by-model basis with the help of the restoring forces of the steered wheels.

The new steer-by-wire system from Mercedes-Benz has already completed more than one million test kilometres on test benches. On top of that is a similar number of test kilometres on proving grounds and in the validation of complete vehicles in road traffic. In line with its high safety standards, Mercedes Benz relies on a redundant system architecture in addition to high-precision sensors and high-performance control units. This means that there are basically two signal paths and thus twice the number of actuators required, as well as a redundant on-board data and power supply. This always ensures steering ability. Even in the most unlikely event of a complete failure, lateral guidance is still possible thanks to rear-axle steering and targeted wheel-specific braking interventions via ESP.