Rear-Wheel Steering / Active Steering

Rear-wheel steering, also referred to as active steering, is a chassis technology that enables the rear wheels to actively assist in steering. Rather than turning at wide angles like the front wheels, it applies subtle angular adjustments (typically between ±3° and ±10°) to cleverly alter vehicle dynamics—making large vehicles significantly more agile and smaller cars more planted.

💡 Two Modes: Low-Speed Manoeuvrability and High-Speed Stability

The real brilliance of rear-wheel steering lies in how it automatically adjusts the rear wheels' steering angle based on vehicle speed, delivering two distinct operational characteristics:

1. At Low Speeds: Counter-Phase Steering (Agility Mode)

   • How It Works: When travelling below roughly 60 km/h, the rear wheels turn slightly in the opposite direction to the front wheels.

   • Real-World Benefit: This effectively shortens the vehicle's virtual wheelbase, drastically tightening the turning radius. For instance, the XPENG X9—which measures over 5 metres long—achieves a turning circle of just 5.4 metres with rear-wheel steering, putting it on par with a compact car. This allows large MPVs and SUVs to effortlessly make U-turns, tackle narrow alleys, and squeeze into tight parking bays without the cumbersome feel typical of large vehicles.

2. At High Speeds: In-Phase Steering (Stability Mode)

   • How It Works: When cruising above approximately 80 km/h, the rear wheels steer in the same direction as the front wheels.

   • Real-World Benefit: This virtually extends the wheelbase, improving rear-end tracking during high-speed lane changes and fast sweeping corners. By effectively curbing any tendency to fishtail, it delivers greater high-speed composure and driver confidence.

🚗 From "Supercar Exclusive" to "Mainstream Tech"

Previously, due to high engineering and hardware costs, rear-wheel steering was reserved exclusively for high-end luxury models and sports cars in the RM1,000,000 bracket, such as the Porsche 911, Lamborghini supercars, and the Mercedes-Benz S-Class. Today, the technology has seen rapid adoption across Chinese electric vehicles, lowering the entry threshold significantly.

For example, the IM L6 has brought rear-wheel steering into the RM200,000 segment, while models like the Lynk & Co 900, XPENG X9, and Denza N9 offer it as standard in the RM300,000 to RM400,000 range. Recent debuts such as the Audi E7X and SAIC Volkswagen ID.ERA 9X also highlight rear-wheel steering as a core selling point, granting full-size 5-metre vehicles the agility of a compact hatchback.

🤔 Why Isn't It Standard Everywhere Yet?

Despite its clear dynamics advantages, global market penetration of rear-wheel steering is estimated at only around 1.2%. Key hurdles include:

• Packaging and Cost: Integrating dedicated actuator motors, electronic control units (ECUs), and sensors onto the rear axle inevitably drives up manufacturing and vehicle costs.

• Space Packaging and Calibration: The hardware eats into boot and under-chassis space. Furthermore, the complex electronic control calibration and integration with systems like Electronic Stability Programme (ESP) demand high-level engineering capabilities from manufacturers.

In summary, rear-wheel steering is a game-changing chassis enhancement for large vehicles. As technology matures and component costs fall, it is steadily trickling down to mainstream segments, serving as a key benchmark of a manufacturer's chassis engineering commitment—especially in larger vehicles.