When it rains it pours. I hadn't driven a KDSS-equipped 4x4 in over a year, but now we've had two in two weeks. It's not because we now have an RTI ramp; it just worked out that way.
I'm not complaining.
The first time I drove Toyota's KDSS (Kinetic Dynamic Suspension System) was back in late 2007, when the fully redesigned 2008 Toyota Land Cruiser was introduced. All Cruisers from that point forward have come standard with KDSS.
The operating principle is exactly the same as the 2011 Lexus GX 460 we saw last week. But the 200-series Land Cruiser platform used here is different from the 150-series Land Cruiser Prado platform that underpins the GX; that fact will become clear when you see how the stabilizer bars differ in this KDSS application.
Instead of the one-piece bars used in the GX, the 200-series Land Cruiser KDSS system uses two-piece stabilizer bars. The major portion of the front stabilizer bar (green) spans the chassis and extends to the other side where it connects to the lower control arm via a standard link in the usual way.
But on this side it bends forward to meet a hinged joint that connects to a second piece that doubles back and extends to the link on this side. Along the way it bolts to the lower eye of the KDSS cylinder.
On asphalt, cornering and the equal front-rear pressures that are created keep this cylinder rigid, creating a fixed pivot point that sits directly in line with the main stabilizer bar bushings. In this way the two pieces act as one and the stabilzer bar operates normally.
The big pressure differential created by opposite-phase off-road conditions causes a valve to open, which in turn allows the KDSS cylinder and the lower eye pivot point for the bar to float. This essentially breaks the stabilizer bar in two and shuts off its ability to generate any roll-resisting torque.
Still not feeling it? Maybe this Toyota illustration from the original 2008 press kit will help. When the cylinder goes limp the blue bar is free to flop around aimlessly in response to the motion of the left front tire. At this point the bolted joint at the blue arrow is a mere hinge.
When the KDSS cylinder is rigid, however, the two halves of the bar behave as one because all the pivot points are lined up along the yellow axis. Through it all the hinge indicated by the blue arrow can move about however it needs to because it's a floating point that's not bolted to the chassis in any way.
Determined to throw us off the scent, it seems, Toyota uses a slightly different two-piece KDSS approach in back. Here a kind of teeter-totter link pivots at a fixed point (yellow) just forward of the rear cylinder (green) attachment point. When the cylinder is rigid the entire link and, crucially, the point where it attaches to the stabilizer bar (blue) remains fixed in space. An unmoving blue point allows the rear stabilizer bar to build torque in corners.
Conversely a limp cylinder allows the link and its endpoint (blue) to float around, preventing the stabilzer bar from creating any resistance.
Huge amounts of articulation, particularly at the rear where a solid axle is found, is the result.
And the numbers are good. So good, in fact, that this 200-series Land Cruiser is the new leader among stock unmodified vehicles we've tested, with a raw score 24.81 inches of wheel lift. That translates to a trip of 72.6 inches up the face of our RTI ramp.
Factor in the Cruiser's 112.2-inch wheelbase and the Ramp Travel Index works out to 647 -- also tops so far in the stock category. Not bad at all for something with this much wheelbase.
So far only our short-wheelbase 2-door Wrangler has done better, but only after it was fitted with big tires, a widened track and had its front stabilizer bar manually disconnected. The Wrangler was also greatly helped by the fact that it has a solid front axle instead of the Land Cruiser' independent front suspension.
Of course the Land Cruiser rides and handles far better than a modified Jeep Wrangler (or a stock one) on the road, but that's not what the RTI test is all about.
Sadly, the mighty Land Cruiser and its trick suspension have nevertheless been afflicted with Highlander's Disease. The too-smooth body styling includes the same sort of integrated wraparound plastic bumpers we saw on the 2011 Lexus GX 460.
This risk of scraping and damage associated with this choice is further compounded by a marked loss of departure angle, which dropped from 24 to 20 degrees when this bodywork was introduced in 2008. What's more, the 200-series Cruiser makes do with nearly an inch less ground clearance than the generation before and a full 1.9 inches less than the 80-series Cruiser that preceeded them both.
Still, when these are 15 years old, I'm sure the aftermarket will have worked something out. KDSS is too good to ignore.
bimmerjay says:
10:54 AM, 01/27/12
Wow that's some amazing articulation.
fantastic says:
11:02 AM, 01/27/12
Fantastic.... that's all!
bradyholt says:
11:45 AM, 01/27/12
I wonder how much the Infiniti QX carries over from the Nissan Patrol. Of course, if it's any better than this, you're gonna need a bigger ramp.
ctpaul says:
11:47 AM, 01/27/12
Would be a major bummer if that cylinder malfunctioned, going limp and disabling the stabilizer bar when you need it for cornering.
dinobot666 says:
12:26 PM, 01/27/12
I'm way more impressed than I thought I would be. If you ever did have to venture off-road with one of these, you'd be doing quite well. Some more aggressive tires would help too.
desmolicious says:
12:37 PM, 01/27/12
" this 200-series Land Cruiser is the new leader among stock unmodified vehicles we've tested"
Which is why you need to test the Jeep Rubicon
desmolicious says:
12:40 PM, 01/27/12
p.s. please try and get your hands on a Benz G550 for an RTI test..
stovt001 says:
12:48 PM, 01/27/12
+1 to the G550.
bankerdanny says:
03:09 PM, 01/27/12
Jeep aims its vehicles at the US driver and US market and is designed with mountain trails like the Rubicon and the slick rock of Utah in mind (even if most drivers won't ever get near either place).
I wonder if Toyota thinks more about Africa, where angles of approach and departure may be less important than good axle articulation over heavily rutted roads.
carchatter1 says:
08:09 AM, 01/28/12
For roughly $70,000 (!) for a base model....it had better have a few trick features.
blackdynamite1 says:
11:49 PM, 01/28/12
The Land Crusher
The King of Off-Roders
BD
aspade says:
03:48 PM, 01/29/12
Wish they sold this as a Toyota.
Instead of a Lexus, and a Lexus rebadged as a Toyota.
frazier500 says:
09:36 PM, 01/29/12
I don't forsee a G550 outdoing this vehicle at all. They don't actually have THAT much suspension travel. Would be nice to see if the LR4's cross linked air suspension helps out any though...
dannyzrc says:
11:14 PM, 01/29/12
Lexus GX470 with sport package also has KDSS, as does the new 5th gen 4runner trail edition.
lostboyz says:
03:55 AM, 01/30/12
bankerdanny has it right, articulation is one thing but the angle of approach on this compared to the jeep is laughable. The jeep can improve articulation, you can't really improve approach angle that much.
x_defector says:
07:18 AM, 01/30/12
That's about as good as one could hope to see in an IFS vehicle. The fact that it is also factory stock makes it all the more impressive.
Again, though, mostly for naught. Despite the fact that most Americans' agenda does not include overlanding adventures, even if one does elect to take their 70k station wagon off road they will soon be looking a multi-thousand dollar repair bill to replace the front and rear bumper fascias. Kind of sad and weird.