Mercedes-Benz Revolutionizes Rear-wheel Steering in the 2021 S-Class

Among those innovations is the revolutionary rear-wheel steering system that takes all-wheel steering to a whole new dimension, offering approximately 15% more direct steering ratio to the front wheels than earlier versions. It also introduces an all-new 10-degree turn angle for the rear axle.

The magic comes from an electric motor that drives a rod from the rear axle with the help of a drive belt. Active telemetry from the radar, cameras, and ultrasonic sensors is fed into the system, which adapts the steering angle to the relevant situation. It switches from counter-direction to same-direction steering and the other way around, depending on traveling speed.

Seeing the rear wheels turning to such an angle might take some getting used to, especially for onlookers, but it will help maneuver the 7-foot-long flagship as well as a much smaller car. The turning circle of the car is decreased by 6.5 feet (2 meters) resulting in roughly the same turning circle as the much smaller A-Class.

This is achieved by moving the rear wheels in the opposite direction as the front axle at speeds below 37 mph (60 kph). When parking, owners have the choice to take their hands off the wheel and let the Active Parking Assist manage what could be a tight situation or even do it from outside the car, by using the Intelligent Park Pilot system via a smartphone app.

But for those who want to truly enjoy the rear steering feature and feel like they're distorting space-time by parking quickly and efficiently in confined spaces, taking the reins and fully controlling the parking maneuvers is possible and highly encouraged.

On the open road, at speeds above 37 mph (60 kph), the rear wheels will move in the same direction as the front axle to improve and maximize stability. It also reduces sideslip angles, without compromising steering precision so it will prove useful if the highway is packed but there’s still enough room for some quick overtakes.

The all-new S-Class is a considerably safer drive at high speeds and has increased agility and overall stability thanks to the harmonious tandem between the front and the rear steering.

Costumers won’t be able to enjoy this option on the base model but those who opt to pay up to an extra $17,700 (16.000 €) will be able to choose from two versions with different maximum rear steering angles:

The 4.5 degrees version, which is based on preexisting technology, offers a turning radius of 38 feet (11.6 meters), and the revolutionary 10-degree version, a rear steering angle that is unprecedented in luxury sedans, which has an even smaller turning radius, at 35 feet (10.8 meters). These dimensions increase by a few inches for the long-wheelbase chassis.

It’s also worth noting that the 10-degree variant has a limited wheel size at 20 inche,s which can only be fitted with tires that won’t exceed the 255/40 dimensions, to allow a larger wheel angle.

The technology is not new, and this isn’t the first S-Class that features rear-axle steering but the dramatic 10 degree turning angle makes the 2021 version of the legendary model the most maneuverable luxury sedan Mercedes-Benz has ever built.