Rear-wheel steering isn't a new technology as it has been around for decades, with the Nissan R31 Skyline pioneering the system back in 1985. That said, Mercedes has managed to take it to a whole new level with its flagship combustion and electric cars, as the latest S-Class and EQS boast the most advanced version ever fitted to a production vehicle.
On the EQS, the rear wheels have a standard steering angle of up to 4.5 degrees, but in other markets, it comes with an optional feature increasing the angle to 10 degrees – this advanced tech is actually standard on the US-market car, however. In the case of the EV, the turning circle drops to 10.9 meters (35.7 feet), which is mighty impressive for such a large car. It turns the rear wheels in the opposite direction to the front wheels at speeds of up to 60 km/h (37 mph) to reduce the turning circle. Above that velocity, all four wheels turn in the same direction to improve stability and sharpen up handling.
How does it work? According to Mercedes: "An electric motor drives a spindle at the rear axle via a drive belt. This makes axial adjustments to the spindle."
Gallery: 2022 Mercedes-Benz EQS
The more advanced setup is offered as standard equipment in the United States, but at home in Germany, the EQS comes fitted with the lesser configuration of RWS. You can have 10-degree steering as an optional feature when ordering the car, and Mercedes is providing another way to gain access to the tech even after taking delivery of the fullsize electric sedan.
With cars becoming rolling computers, Mercedes is cramming more and more tech while providing support for over-the-air updates. The EQS is a relevant example as owners can activate the 10-degree rear-wheel steering post-purchase courtesy of an OTA update. It effectively means the vehicle has this feature from the get-go, but it's blocked by the software. Unlocking it costs €489 (about $575) annually, but if you get a three-year subscription, you'll get a €300 ($353) discount by paying only €1,169 ($1,376).
Ordering the more sophisticated steering system requires the parking package with a 360-degree camera, as it's the case with the S-Class. Interestingly, the tech can't be had if the car is running on mixed tires, which isn't the case for EQS as only its combustion-engined equivalent uses that type of rubber. Activating all-wheel steering takes about two minutes after turning off the car before switching it on again.
It's a bit frustrating to know your car already has this feature and yet you can't use it, but on the other hand, the flexibility offered by OTA updates is great. Mercedes is not the first automaker to go down the pay-to-use road and it certainly won't be the last. In a not-too-distant feature, Volkswagen might charge you roughly $8 for one hour of access to autonomous driving tech.
It’s a brave new world out there.