BIG WATER, Utah — On the specification sheet for the 2013 Range Rover is an entry you don’t often see applied to a luxury vehicle: wading depth, 35.4 inches.

The number coincides with one of the tests performed by engineers during the development of the new Range Rover. The opulently outfitted S.U.V.— the pinnacle of Land Rover’s blue-blood model line — is driven into nearly three feet of standing water, its ignition turned off and the door opened, allowing the interior to flood.After 30 minutes, the engine is restarted and the vehicle is driven out of the water, demonstrating its ability to endure even the most extreme conditions.
Besides the water torture routine, a Range Rover must prove its ability to pull through axle-deep mud and sand, maintain its grip through ice and snow, crawl up and over huge boulders and churn through heaps of debris.
Yes, Land Rover’s flagship, the subject of a complete redesign for 2013, still has the capability to carry occupants to all sorts of places where most owners would never dream of driving their six-figure luxury vehicle.
Land Rover says that fewer than 10 percent of owners ever take their Range Rovers off-road, much less punish them with expedition-caliber terrain. Indeed, romping through muddy bogs, blasting across sand dunes or fording deep streams might well be seen as irresponsible.
On a long off-highway test-drive here in the mountains of southern Utah, during which I sampled a variety of surfaces that included red clay the consistency of gumbo, it occurred to me that it may be enough to just know that a Range Rover can handle almost anything its owners may ncounter. It’s entirely O.K. with me that it is rarely called upon to do so.
But it is with the possibility of blizzards, flooded roadways and combat-zone pavement gaps in mind that the company has built such a high degree of versatility into this model.
A Range Rover redesign is a rare occurrence; the 2013 model is the fourth generation of a nameplate first sold in Europe in 1970. The previous model was still selling well, but technology had advanced sufficiently to warrant a complete makeover.
In laying out the guidelines for the redesign, Land Rover management told its engineers and stylists to change everything — except the looks. In my view, they succeeded: its girth may appear a bit more full (it’s actually within fractions of an inch of previous measurements), but over all the Range Rover maintains its characteristic stance.
The most pressing issue, and the matter to which the greatest amount of engineering effort was devoted, was weight reduction.
Not that fuel economy and curb weight are crucial considerations for Range Rover buyers, but at three tons, the previous version was ponderous on the road. Its affinity for visiting gas stations was, at the least, a nuisance, if not a financial concern, to its well-heeled owners.
So the steel body has been replaced by an all-aluminum unibody structure that is 39 percent lighter, part of an overall weight reduction of 700 pounds, and according to Land Rover, will uphold the company’s hard-earned reputation for toughness.
The weight savings pay dividends in handling, acceleration and, Land Rover says, a 9 percent improvement in fuel economy — now 14 miles per gallon in town and 20 on the highway for the standard V-8; with the supercharged V-8, consumption drops to 13 city, 19 highway.
Those 5-liter engines carry over from last year’s model with ratings of 375 and 510 horsepower; having much less bulk to push down the road for 2013, they feel unchained. Zero to 60 m.p.h. times are quicker by nearly a second — now 6.5 and 5.1 seconds respectively. For model year 2014, the base V-8 will be replaced by a 340-horsepower supercharged V-6, and all models will get an idle stop-start feature.
Also playing roles in the improved efficiency are a new Bosch engine-management system, the latest direct-fuel-injection technology and an 8-speed automatic transmission. Steering wheel-mounted paddle shifters offer manual gear selection, though the transmission seemed to intuitively, and almost imperceptibly, choose the appropriate gear on its own, even while descending a steep mountain switchback.
A reworking of the air suspension, including new springs at the front, helps the Range Rover corner more confidently, though that is offset by the new electric power steering system, which has a disappointingly numb feel. Still, at its new fighting weight the top Rover feels almost like a sport-tuned BMW X Series S.U.V. on the road — and less like a Hummer off it.
A new version of the adaptive Terrain Response system, which adjusts the engine, transmission, differential and chassis controls for varying surfaces, adds an automatic mode. Still, it cannot read and anticipate terrain as a human does, so manual control is retained for sand, mud, snow and rock-crawling situations. I spent 90 percent of my off-road drive in the sand setting, which handled most anything I chose to tackle.
Approach and departure angles — measurements that indicate the degree of difficult terrain a vehicle can handle — are improved, and a multiple-setting height adjustment can increase the ground clearance by nearly 3 inches for tricky off-road situations. Wheel options of up to 22-inch diameters are offered, though all of my ambitious off-road antics were successfully completed on standard all-season tires.
A suite of hard-core all-terrain systems assists the driver when the going gets toughest: Hill Descent Control, Gradient Release Control, Hill Start Assist, Roll Stability Control and stability and traction control. A new Bosch antilock braking system enhances all these functions and helps the vehicle stop promptly, with great on-road control.
The full-time 4-wheel-drive system has a 2-speed transfer case with a locking center differential. Torque, nominally split 50-50, can be shifted by a multiplate clutch as needed to make the best use of the available traction.
I could go on. But the full set of technical descriptions can — and does — fill a thin book. I’m waiting for the Kindle version.
My favorite feature of the new Range Rover is subjective, not technical. The interior is even more luxurious than before. And I think this is where the company is to be applauded: while some automakers continually scrimp, save and cost-cut on luxury items, it seems that Land Rover has not, at least as far as the Range Rover is concerned.
The top — rather fussily named — Autobiography model now starts at $130,995. Given the brand’s strong sales, it seems that Land Rover’s demographic of ultrahigh-net-worth individuals have a rationale that justifies paying for yards of matched wood trim, Bridge of Weir semianiline leather upholstery, heated and cooled massaging seats, a center console beverage cooler, parallel-parking assistance, rear-seat entertainment, an 825-watt sound system (a 1,700-watt upgrade is a further $4,500) and a concierge-level list of other amenities.
Of course an adequately equipped base model, the HSE, can be purchased for a somewhat less breathtaking sum, $83,545. Land Rover reports that fully 50 percent of Range Rovers “go out the door under $100,000.”
For those seeking a lower price point, the company also offers the Range Rover Sport, a somewhat smaller, sportier version with slightly reduced off-road capability, fewer electronic helpers and less wood and leather for a saving of about $20,000.
If anything, the comparatively high price is an attraction of the Range Rover. It helps keep the clientele exclusive, a fact that probably enhances, rather than hinders, its appeal.
But keep this in mind: at any price, a Range Rover buyer is probably getting more capability than is needed. And there may be opportunities — crossing three feet of standing water, for instance — when it may be more prudent not to use this vehicle as intended.