Surprising Tech Behind the New BMW M5: How Rear-Wheel Steering Changes the Game
The buzz around the latest BMW M5 has primarily focused on its enormous power and hefty weight, but there's a crucial piece of technology that’s been too easily overlooked—rear-wheel steering. The G90 M5 is not only the first M5 to showcase this feature but also just the second M car to incorporate it, following the groundbreaking XM.
To delve deeper, we had a chat with Dirk Häcker, the engineering maestro at BMW’s M division, who explained the necessity of this addition. The M5’s jump in size necessitated BMW to introduce Integral Active Steering. This isn’t just your everyday sedan; it’s practically an unofficial M7, boasting dimensions of 5096 millimeters (200.6 inches) in length, 1970 mm (77.6 in) in width, and 1510 mm (59.4 in) in height. With a staggering wheelbase of 3006 mm (118.3 in), maneuvering this sports sedan in tight spaces can be a Herculean task.
The magic of rear-wheel steering comes in its ability to pivot the rear wheels up to 1.5 degrees, slashing the turning circle down to 12.6 meters or 41.3 feet. Remarkably, this matches the turning circle of the previous-generation M5, despite the G90’s larger footprint. But the benefits don’t end there. This feature enhances stability and comfort during high-speed cornering. When traveling below 35 mph (56 km/h), the rear wheels turn in the opposite direction to the front wheels, aiding in nimble low-speed maneuvering.
At higher speeds, the rear wheels pivot in the same direction as the front wheels, contributing to a more stable and agile driving experience. Dirk Häcker assures us that this technology helps the G90 feel comparably agile to its predecessor, the F90, even though it’s a significant 1,045 pounds (474 kilograms) heavier when comparing US-spec models. It’s an intriguing statement that begs enthusiasts to get behind the wheel and experience it firsthand.
It’s worth noting that several non-M BMW models also boast Integral Active Steering, operating at more extreme angles of up to 3.5 degrees. However, in this battle of giants, BMW’s archrival Mercedes pulls ahead with a more sophisticated system capable of turning rear wheels by as much as 10 degrees. This isn’t a new game, though. The technology was pioneered by Japanese brands in the 1980s, with the third-generation Honda Prelude and Mitsubishi 3000 GT making it well-known. Even BMW dabbled with it during the same era, introducing the Aktive Hinterachs-Kinematik (AHK) system in the 8 Series E31.
Looking ahead, we expect the forthcoming M5 Touring G99 to come with rear-wheel steering straight out of the factory, a move that promises to deliver an unparalleled combination of agility and stability. As the landscape of high-performance sedans continues to evolve, it’s innovations like these that set the stage for what enthusiasts can expect in the future. Rear-wheel steering in the new M5 isn’t just a tech upgrade—it’s a revolution that redefines what’s possible for sports sedans.