From 80 series to 300 series, all Land Cruiser wagons for the past 30+ years have had one thing in common: A 112.2 inch wheelbase. Toyota calls this wheelbase and the overall length it dictates the “golden ratio.” The new 2024 GX550 — for which we’ll publish a review tomorrow here on The Autopian — has moved up in size slightly and occupies the same 112.2 wheelbase. In fact it’s very close dimensionally to the 80 series in most respects; but why is that wheelbase a big deal, or does it really matter?
I recently had an opportunity to interview the GX lead engineer, Koji Tsukasaki, and among the topics of discussion arose the change in wheelbase (which has grown from 109.8 in the 4Runner and past GX) and why that change is important.
“If it’s too short, you lose straight-line stability, if it’s too long, when you are off-road you have a tendency to hit. We found that 2850 [mm] is the best balance…” he told me.
Mathematically, Toyota misses the more famous golden ratio of Euclidean fame of 1.618, but it’s very close, hovering around 1.71 depending on year (overall length divided by wheelbase). However it wasn’t the fibonacci sequence that drew out this ideal wheelbase ratio, but “cumulative experience,” according to Tsukasaki.
“It turned out to be the most ideal…And so for us we felt that that was the appropriate wheelbase packaging to bring into this new car to achieve the same goals.”
Lexus is serious in making this model a full-fledged touring machine, and what better place to borrow than the Land Cruiser which enjoys a strong reputation for being a good sized, well rounded off-road touring machine.
So why does it matter? Wheelbase, like most things, is a compromise. A small wheelbase produces a very nimble off-roader that darts around on trails with a good steering radius and a great breakover angle, preventing hangup. On road, though, they are a bit less stable, more prone to rolling both on and off-road, and are limited in their utility by their short size and the dynamic limits of such a wheelbase restricting tow capacity, cargo capacity and people capacity.
A short wheelbase also provides for a choppy ride, as the forces that activate the front and rear suspensions are more closely coupled. A long wheelbase on the other hand provides stability and ride quality both on and off-road, and allows for greater utility through volume and capacity to tow and haul, but compromises breakover and maneuverability.
Then there is also the overall length to consider. A 112.2 inch wheelbase wouldn’t mean much on a 225 inch Suburban, as the approach and departure angles would be awful thanks to giant overhangs.
In the same vein, a longer wheelbase on a shorter overall length may net you excellent approach and departure angles, but your breakover angle and overall maneuverability would suffer.
A good example is the relatively short 188.4 inch long Jeep Wrangler 4-door with a relatively long 118.4 inch wheelbase. With 43.9 and 37 degrees of approach and departure, respectively, it is easily one of the best in its class, owing to axles pushed to the ends of the frame, but a breakover angle of 22.6 and a large turning radius are tradeoffs.
However, a short wheelbase Wrangler Rubicon with similar approach and departure angles benefits from a more favorable wheelbase to length ratio and has a much more balanced 27.8 degrees of breakover. The tradeoff of course is that you are limited by 166 inches of off-roader with limited towing and cargo capacity and all the negatives of a short wheelbase.
The GX550 features a more rounded set of figures. For an overall length of 197 inches, a 112.2 inch wheelbase and similar size tires as the above Wrangler nets more modest approach and departure angles of 26 and 22, respectively, but a decent 24 degrees of breakover.
As with most things, “ideal” is relative to the intended use and personal preference. For touring, Toyota seems to have found their formula, and while the long rear ends and low departure angles are a common gripe in the Land Cruiser community (see an old 100 Series drag its rear in the clip below), it has generally proven to be a winning combination for overland travel.
David Tracy tells me that Jeepers have a similar “golden wheelbase” of about 101.4 to 103 inches. And no, it doesn’t surprise me that it’s a totally different figure than Toyota. For one, Jeepers are weird. But more seriously, their use case is totally different, and traditional off-roading is more a priority to towing or long haul off-roading. I will say that I think it’s interesting that the ratio of length to wheelbase on what many Jeepers consider the ideal size Jeep, the LJ, is 1.71, hmmmm.
[Editor’s Note: I think Land Cruisers have too big of an ass, but that’s because I like doing harder off-roading than most Land Cruisers tend to see, and I can’t have that huge liability of a departure angle. I get it; if Toyota stretched the wheelbase, the belly would become a vulnerability. If they just reduced the overhang, they’d lose interior space. Do I think there’s a true perfect wheelbase? No. It depends on too many factors, like how much space that powertrain up front takes up, the packaging requirements of the cooling module you need to meet your towing requirements, the interior volume you want, the overall width you want, the capability you want — it’s a complicated thing. I personally prefer a shorter wheelbase and a shorter overall car, but I also don’t need as much interior volume, and I demand more off-road capability. -DT].
As for Toyota, I find it fascinating that they stick to this wheelbase with such fervor, but anything that keeps model bloat in check, especially off-road, is a win in my book.