Lexus IS may get four-wheel steer

Lexus believes four-wheel steer could give it the edge over its competitors in the competitive sports sedan segment. The system has the rear wheels turn at the same time as the front ones -- but only a small amount -- to help the car through corners.

The idea gained some traction with Japanese car makers in the 80s, notably with cars like the Honda Prelude and Mazda MX-6 coupe. At the time, it was touted as the next big thing but the system was clunky and could be expensive to repair if things went wrong.

That was then this is now. Technology has moved on and BMW already offers the system with its 5 and 7 Series models and Lexus introduced four-wheel steer in the first of its cars last year with its GS line.

It has also been trialling the system in the smaller IS range in Japan and the Australian arm of the company is keen to get a piece of that action. Lexus Australia boss Sean Hanley believes it could give the car a much-needed competitive edge.

HOW IT WORKS

Lexus calls its system Dynamic Rear Steering (DRS), and has it turn the rear wheels of the car two per cent – a seemingly tiny amount but enough to make a difference to the cornering. At low speeds the rear wheels turn in the opposite direction to the front wheels to reduce the car's turning circle and the level of steering effort required.

But at speeds of more than 80km/h, the rear wheels turn in the same direction as the front wheels. This makes the steering more responsiveness and gives it an intuitive feel at medium speeds, plus greater stability and vehicle posture for increased safety and comfort at higher speeds.

The net result is the turning circle is reduced by almost half a metre at parking speeds and it also reduces the tendency of rear wheel drive vehicles like those produced by Lexus to step out or oversteer in a corner. We had the opportunity to put a car fitted with the rear wheel steer system through its paces on a recent trip to Japan. Unfortunately we had no car with standard steering to compare it with and Lexus has apparently not quantified the difference it makes to track times (although we thought that would have been an obvious thing to do). Having said that the car was plenty of fun to drive.

WHEN MIGHT WE SEE IT HERE?

Lexus wants to add the system to its F Sport models. "We think it gives us another progressive edge in the market place," Hanley says. "And the other thing is that it is significantly well developed now. So we're bringing to market a very credible technology, with great safety and performance that is aligned very very well to Lexus's innovative and fun to drive performance car strategy."

At this stage the system is available only in Japan but it is under evaluation for other markets. If it is approved for overseas use it is likely to find its way into Aussie cars within the next year or so, probably when the car receives its mid-life facelift. Rear or four-wheel steer is part of the Lexus Dynamic handling System (LDHS) that features the world's first integration of Dynamic Rear Steering (DRS), Adaptive Variable Suspension (AVS), Variable Gear Ratio Steering (VGRS) and Electric Power Steering (EPS}.