How does the Land Cruiser’s Kinetic Dynamic Suspension System work?

Is it possible for a four-wheel drive vehicle like the Toyota Land Cruiser to possess flat, confidence-inspiring handling characteristics on the road and yet offer generous axle articulation during off-road use?

2015 Land Cruiser front

Traditionally, these are mutually exclusive qualities. This is partly because the anti-roll bars that connect both sides of the vehicle and help maintain a horizontal cornering attitude for road use also place limits on an individual wheel’s range of vertical travel when negotiating uneven surfaces.

2015 Land Cruiser rear

Toyota’s solution to this seeming paradox is its Kinetic Dynamic Suspension System (KDSS), fitted to Land Cruiser Icon and Invincible models. As the name suggests, KDSS is designed to react dynamically to forces being applied across the suspension, optimising chassis performance whether on- or off-road. It achieves this by using an electrically modulated network of hydraulics to modulate or even disable the anti-roll bars.

2015 Land Cruiser technical

As you can see in the above cutaway and simplified schematic below, a hydraulic cylinder with a separate upper and lower chamber is fitted to each of the Land Cruiser’s anti-roll bars. The upper chambers of the front and rear cylinders are connected by one hydraulic line, while both lower chambers are similarly connected. Each hydraulic line is plumbed with an electronically controlled accumulator valve.

Land Cruiser technical underpinnings

When cornering in normal road use, equal pressure is applied to the outer wheels. As a result, the hydraulic fluid remains still within the lines, holding the front and rear cylinder pistons in place. This allows the anti-roll bars to twist as normal, suppressing the suspension stroke and reducing body roll, improving the feeling of stability. The difference this can make to the car’s angle of attitude is pictured below.

Land Cruiser anti-roll bars

On rougher roads, slightly uneven forces are exerted between the front and rear wheels. When this is sensed, the accumulator valves rapidly open and close to control fluid movement within the hydraulic lines. This dampens vibrations by absorbing surface undulations, delivering a more comfortable ride.

2015 Land Cruiser schematic

In the more serious off-road condition illustrated above, the wheels are at different heights in relation to one another. This generates unequal forces between and across the axles, causing the pistons in each hydraulic cylinder to stroke in opposite directions. This counteracts the normal resistance of the anti-roll bar and allows maximum articulation of the suspension. With both front and rear anti-roll bars now effectively disengaged, all four wheels can remain in contact with the ground for as long as possible.

2015 Land Cruiser off-road

Toyota models equipped with KDSS therefore enjoy optimised on-road stability as well as greater freedom and ability in extreme off-road situations.

Learn more: History of the Toyota Land Cruiser

9 comments

  1. Hi my name is Siva an alignment technician .have problem with landcruiser 200 series.it was low on the right driver side so we jacked the right side up and loosened the shutter valves on the KDSS now it’s too low on the left.difference is about 40mm is there any way of correcting or raising the left to where it was.please assist or advise if you can thanks.

    1. Hi Siva,
      Thanks for getting in touch.
      We can only advise on UK specification vehicles, so we would recommend contacting the Toyota distributor in your region for further help with your query.
      Thanks.

    2. Siva
      Also having a problem with levelling my 200 series – please advise if you found a solution
      Thanks
      Rob

    1. Hi Martin,
      Thanks for getting in touch with us.
      If you could provide us with your UK reg, we can then look into this for you.
      Thanks.

  2. Hi. I am interested in a 2010 LC5 150 in the UK. Does KDSS come as standard on those? VK10 EPF

  3. Hello 👋🏿 Toyota, I have a Toyota Prado TX.G with Air Suspension Boosters, and I have had a hard time making sure they balance because the RHS booster is always hits low whenever I use rugged roads. Can you please help me out?

    1. Hi Ggaayi,
      Thanks for your comment.
      Unfortunately, we can only advise on UK specification vehicles.
      Please contact Toyota in your region.
      Thanks.

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