With all the debate regarding the new M5’s massive power and weight, it’s easy to omit other interesting details. The G90 is the first M5 to have rear-wheel steering and only the second M car to have this feature, after the XM. BMWBLOG chatted with the engineering boss at the M division to find out why this piece of hardware was added.
Dirk Häcker explained Integral Active Steering was born of necessity following the M5’s jump in size. We previously labeled the car as an unofficial M7 since it’s 5096 millimeters (200.6 inches) long, 1970 mm (77.6 in) wide, and 1510 mm (59.4 in) tall. With a massive wheelbase of 3006 mm (118.3 in), it’s trickier to maneuver the sports sedan in a tight spot. It’s especially true considering the M5 is the first to have wider tracks compared to the regular 5 Series Sedan.
By turning the rear wheels up to 1.5 degrees, the turning circle is reduced. At 12.6 meters or 41.3 feet, the turning circle matches that of the previous-generation M5, despite the new car’s bigger footprint. We’re being told it’s also more stable and comfortable during high-speed cornering. At speeds below 35 mph (56 km/h), the rear wheels turn in the opposite direction of the front ones.
At higher speeds, they pivot in the same direction as the front wheels. Dirk Häcker also told us it’ll help the car feel comparable to its “F90” predecessor in terms of handling and agility. It’s an interesting statement considering the “G90” is 1,045 pounds (474 kilograms) heavier if we’re comparing US-spec cars.
Several non-M models boast Integral Active Steering that works at up to 3.5 degrees. BMW’s archrival Mercedes has a more sophisticated setup that turns the rear wheels by as much as 10 degrees. The technology was pioneered by Japanese brands back in the 1980s. The third-generation Honda Prelude made this feature better known, and so did the Mitsubishi 3000 GT. Lest we forget that roughly around the same time, the 8 Series E31 got the Aktive Hinterachs-Kinematik (AHK) system co-developed with Bosch.
We expect the upcoming M5 Touring G99 to have rear-wheel steering out of the box as well.