Another day, another acronym that is too long to cover in one sentence, but allow us to explain why you should care about the Lexus GX 550 Overtrail and its E-KDSS (Electronic Kinetic Dynamic Suspension System).
The acronym KDSS (Kinetic Dynamic Suspension System) has been commercially available since 2002, but Chris Heyring is credited with the idea, fitting the first prototype to a 1990 Toyota Hilux. An R&D company called Kinetic Pty Ltd, based in Dunsborough, Western Australia, further developed this concept, which was first used on the Lexus GX 470 back in 2004 as an optional extra. It quickly became a standard feature in future models due to the significant on-road stability and off-road capability it provided. These benefits were hard to ignore, leading to its rapid adoption in models like the Toyota Land Cruiser, FJ Cruiser, and Land Cruiser Prado variants.
HOW KDSS WORKS
The original KDSS system relied on hydraulic systems to actuate the KDSS movements, making use of hydraulic accumulators and cylinders, moving hydraulic fluid back and forth, compressing and extending a shock mounted on the rear and front swaybars, disconnecting the swaybars from the suspension system, allowing for the unrestricted travel of the suspension system while reducing body roll and controlling wheel extension, increasing on-road stability and off-road wheel articulation. A very handy piece of technology indeed!
Naturally, Lexus and Toyota did not stop there, though. Some restrictions to the original KDSS setup (mainly the hydraulics and the mounting positions of the KDSS system itself) meant that it was prone to rock impacts that could severely damage the swaybars as well as the hydraulic chambers, accumulators and tubing.
EVOLVING CONTROL
To work around this, the brand new Lexus GX 550 comes equipped with Electronic Kinetic Dynamic Suspension System, where the brain has evolved into an Electronic Control Unit (ECU). Electronic actuators replaced the hydraulic actuators, allowing for a more responsive and accurate control of the sway bars. In addition, two electronic control circuits, one for each axle, fully disconnect the front and rear sway bars, allowing for total independent control.
This is good because it allows for a considerable amount more wheel articulation by saving a lot of weight and space, tucking away the sensitive parts of the E-KDSS system behind wheel axles and giving the independent fore and aft suspension even more freedom to do what it needs to do when off-roading.
In addition, the Lexus GX 550 Overtrail’s suspension system has been upgraded as well, so much so that when the E-KDSS system is disconnected, the GX 550 Overtrail still has more off-road wheel articulation than in previous GXs.
FACTORY-FITTED CAPABILITY
No upgrades needed, no wheel arches cut, no fiddling around with ride heights. Stock standard, fresh from the factory, you can take your Lexus GX 550 Overtrail, hit the dirt roads, and comfortably sit back and watch all the heavily modified vehicles struggle to drive half the trails you just did. It is that capable!
Report by RUBEN VON STEEN
Images © TOYOTA SOUTH AFRICA
