Steering the 2027 Mercedes-Benz EQS With Steer-by-Wire: How It Compares to Tesla and Nio

We first felt electric steer-by-wire—where there’s no mechanical link between the wheel in your hands and the steering gear controlling the front wheels—on the 2014 Infiniti Q50. It allowed neat features like an infinitely variable steering ratio and an absence of unwanted feedback (from severe bumps, for example). But the Q50 had a safety net: A full steering column still existed, so that if something went wrong, a clutch reconnected a physical shaft, restoring old fashioned steer-by-steel.

Today, there are a handful of vehicles using systems like this, but the first two to eliminate that reconnectable shaft were the (the 2025 Best Tech–winning) Tesla Cybertruck in North America, and the Nio ET9 in China. Mercedes-Benz is poised to be the first German automaker to offer true by-wire steering, launching first in its 2027 Mercedes-Benz EQS-Class sedan. We’ve driven all three and are ready to compare and contrast them.

Abundant Redundancy

There are at least two of everything in these types of steering systems—two separate DC-DC converters and power supplies, two completely disparate communications circuits, and the motors taking steering input and delivering steering actuation both have two separate stator windings. If a failure is sensed in either of these circuits, the other one takes over. All three companies do at least this much. The Nio ET9 and Mercedes each utilize materially different CPUs, software and in some cases hardware to ensure against a common failure path crippling both circuits. Both also employ a third set of steering angle sensors that remains ready to help decide which of the two main ones is correct, should their signals ever differ (this is an aerospace protocol). It’s also noteworthy that Nio and Mercedes systems are each safety certified by their respective national governing bodies. Tesla has offered less transparency into its system functionality.

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Fail-Safe

In the Mercedes, whenever an error is detected in either circuit, the car enters a limp-in mode restricting speed to 54 mph, with a maximum driving distance chosen to allow an EQS to safely exit Earth’s longest highway tunnel—the 15.2-mile Laerdal in Norway. And in the infinitesimally small likelihood that both systems were to go down simultaneously, the system will utilize rear-wheel steering and selective braking to achieve the driver’s intended path (we know Nio does this, as well, and Tesla may also). Nio’s behavior upon fault detection is similar—force the car over sooner rather than later, while Tesla flashes lots of warnings but allows the driver to continue using the backup system, with less reduction in functionality and no self-parking end-game.

10 Degrees of Rear Wheel Steering

The standard rear steering system for EQS models is set at 4.5 degrees but can be bumped up to 10 degrees via a software upgrade. The steer-by-wire option includes the full 10-degree functionality (same as Cybertruck, ET9 maxes at 8 degrees). Like all such systems, this one steers in the same direction as the fronts at highway speeds to increase vehicle stability and in opposite direction to the fronts at low speed to tighten the turning circle (which is about 40 feet with 4.5 degrees and just under 37 with 10 degrees, as opposed to 43 feet with no rear steer).

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Yoke Steering Standard

Steer-by-wire offers only 170 degrees of steering from lock to lock, and then only at low speeds. Therefore, hands grasping the two sides of the yoke need never cross over, so there’s no need to grab the upper section of a steering wheel rim, and hence no need to include it. This affords a better view of the instrument cluster and more leg clearance when entering and leaving the vehicle. The EQS will continue to offer electromechanical (shaft) steering, and that system continues with a traditional steering wheel. Of course, China now requires a continuous rim steering wheel, so there will be an exception for steer-by-wire in that market.

Unique Features

• Wheel Imbalance Simulation. Say a pothole dislodges a wheel balancing weight or packed snow inside a front wheel sets up an imbalance. A steering column would transmit vibration that would encourage an owner to remedy the situation. In the EQS system, when its sensors detect those types of imbalances, it can replicate a vibration at the wheel to ensure that the owner knows to address the problem.
• Hill Curb Parking. It’s the law in places like San Francisco that when parking on steep hills, the wheels be steered sharply toward the curb. But a vertically turned yoke might make it harder to slide the driver’s legs out, so with the car switched off, when the door opens, the wheel returns to straight ahead. Climb back in, shut the door, power up the car, and the yoke turns to match the front wheels—unless the driver grabs it. In that case, the wheels quickly turn to match the steering yoke position. Note that the rear wheels always return to straight ahead when the vehicle is parked, strictly to keep them from looking weird.

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How the System Feels

We only had the chance to sample the system on a short course with cones placed only slightly farther apart than the length of an EQS. We drove models with and without steer-by-wire (and the cars without only had 4.5-degree rear steer). This exercise highlighted the greatly reduced arm motion required to turn from fully left to fully right. The version with the traditional wheel required considerable arm-over-arm flailing to complete the course, while the by-wire car zipped through with wrists barely touching at each extreme.

Cybertrucks use a steering wheel with a squared-off top and bottom, and the Chinese-market ET9 obviously has a full-rim steering wheel, although its shape is more of a squared circle, as well. Both vehicles preserve much of the yoke’s benefits in terms of entry/egress and (at least for the ET9) instrument visibility. When driving the ET9 and Cybertruck in normal traffic, the Nio proved faster and easier to acclimate to, thanks to its less aggressive steering ratio range—14:1 at low speeds transitioning to 6:1 at high speeds, versus Tesla’s 12:1 in the parking lot and 5:1 on the freeway. The Mercedes-Benz system ranges between 18:1 and 6:1, which suggests it should be even easier to acclimate to than the Nio system.

When and How Much?

The facelifted EQS with optional steer-by-wire goes on sale this September as a 2027 model, but the steer-by-wire function will be released some time after that. Pricing for the by-wire yoke system will not be finalized until closer to its launch, but we would expect it to at least double the current $1,300 cost for the 10-degree rear-axle steering option.