Big news on GM's big SUVs

Good news and bad news for General Motors' large cash cows, the full-sized SUVs. The bad news: The massive sport-ute market has shrunk roughly in half to around 300,000 a year. The good news for GM: This drove some competitors either out of market or into the near-niche category, leaving the new-for-2015 Chevrolet Tahoe and Suburban, the GMC Yukon and Denali, and Cadillac Escalade with a big share of this very profitable segment. We spent some time in Chevrolet and GMC models, both big and extra-big.

What is it?

Surprisingly, GM tells us it is really a segment within a segment -- Tahoe and Yukon buyers seldom cross-shop the bigger Suburban or Yukon XL; and up-level 2015 GMC Denali customers aren't much interested in less-prestigious models, though the only real mechanical difference is the Denali's 6.2-liter, 420-hp V8 instead of the other models' more-than-enough 5.3-liter, 355-horse V8.

The 5.3-liter has about 10 percent more power -- including torque, now up to 383 lb-ft. Still, EPA city and highway mileage each rise 1 and 2 mpg to 16 and 23 on rear-drive models, while four-wheel-drive models -- the lion's share of the product mix -- jumps 1 mpg on the highway to 22 mpg. The Denali, as you'd suspect, is a little thirstier, with the 4x4 EPA-rated 14 mpg city, 20 mpg highway. Depending on the model, four-wheel-drive towing capacities range from 7,900 pounds to 8,400 pounds. Transmission is the smooth-shifting six-speed automatic.

GM designers did a capable job not only maintaining a familial sense with the edgier exterior updates, but they have managed to keep the Chevrolet and GMC models separate enough to satisfy loyalists. Let's face it: Just like with new minivans the designers have to stay within a fairly well-designated box -- no pun intended -- because these are fairly mature, conservative customers, looking more for function and presence than radical new concepts.

Perhaps the most distinctive change in the Suburban and Yukon XL models is that the rearmost seat is no longer removable. It folds flat, but to provide a flat floor when the two rear seats are down, they had to raise the luggage area behind the seats, using a rather flimsy arrangement that at least has some storage beneath it. Once down, it works quite well, though, and no longer do owners have to wrestle the big seat in and out and find a place to store it.

It also gives thieves one less target: The new SUVs have been substantially upgraded in security and safety measures -- some features standard, some optional. One such option is an intrusion alarm. Picture it: You're sitting at an intersection with the window down, and a bad guy runs up and reaches inside the window … and his arm is chopped off! Just kidding: An alarm does sound, though.

What's it like to drive?

Owners satisfied with, say, their 2013 models won't find an immediate and compelling reason to trade in for the new ones, but the driving and riding experience has been improved. Electric power steering proves GM has finally, after an uneven start, gotten the feel right and consistent.

The optional magnetic ride control remains as much a revelation now as when we first experienced it on Cadillacs and Corvettes years ago. Even without it, though, ride and handling improvements make these big boys drive smaller than they are, and that's a compliment. The ride is stunningly quiet, thanks to some serious sound-deadening work, as well as aerodynamics and tire development.

No, you still won't be tempted to visit the nearest autocross event with a full-sized GMC or Chevrolet SUV, but you won't want to avoid winding roads, either. And inside they remain the closest thing to a true Swiss Army knife -- prepared to work, entertain … or carpool.

Do I want one?

You already know the answer -- the question is, do you want this one? Full-sized SUV customers convinced themselves about $2 per gallon ago that they need what these vehicles offer. The choice is: Do you want to trade in today's full-size GM SUV or move over from the handful of remaining competitors?

You do. These Tahoes, Suburbans and Yukons raise the bar in every single area, but they aren't cheap. GM provided only deluxe four-wheel-drive versions for us to test, and the out-the-door prices ranged from $70,085 for a 4x4 Tahoe LTZ to a Yukon Denali XL's $77,470. A rear-wheel-drive Tahoe starts at about $46,000, but options add up quickly.

In this market, price doesn't seem a deterrent, though. Resale value remains healthy, at least if you hang onto these big SUVs for four years or so. Most have, and then some -- full-sized SUVs on the road average more than 10 years old, so there is pent-up demand for new ones. This is good news for GM -- it has good trucks across the board.

2015 Chevrolet Tahoe and Suburban, GMC Yukon and Yukon XL, plus Denali models

On sale: Now

Price: From $45,890 to about $80,000

Engine: 5.3-liter V8, 355-hp, 383 lb-ft of torque on all models except Denali, which has a 6.2-liter V8 with 420 hp, 460 lb-ft

Fuel economy (EPA City/Hwy): 16/23 to 14/20, depending on model and engine

By Steven Cole Smith