2008 Tahoe, Yukon debut as gasoline-electric hybrids

What weighs more than 2 1/2 tons, has seats for up to nine people, looks conspicuously like a big sport utility vehicle and yet is a gasoline-electric hybrid?

It's the 2008 Chevrolet Tahoe Hybrid and its twin, the GMC Yukon Hybrid, which are the largest passenger-carrying hybrids on the consumer market. You might say these new models introduced early in calendar 2008 are the hybrids for big families because gas-electric hybrid cars are limited to five passengers.

Before these models, the largest hybrid SUV -- the Toyota Highlander Hybrid -- was a midsize vehicle with seats for up to seven.

The Tahoe and Yukon Hybrids also are the hybrids for people who need towing power for boats and trailers -- at least small to mid-range boats and trailers that aren't more than 6,200 pounds of tow weight.

The Tahoe and Yukon Hybrids can accomplish this towing because they're based on truck platforms and team large, 6-liter V-8s with electric motor power to generate a hefty 332 horsepower and 367 foot-pounds of torque at 4,100 rpm.

In this photo released by GMC shows the 2008 GMC Yukon Hybrid. (AP Photo/GMC)

In comparison, America's best-selling hybrid, the Toyota Prius, offers just 110 horsepower and peak 295 foot-pounds of torque.

With a starting manufacturer's suggested retail price, including destination charge, of $50,490 for a two-wheel drive Tahoe Hybrid and $50,945 for a two-wheel drive Yukon Hybrid, these new SUVs are more than double the price of a Prius.

But they can be compelling when you compare all you get -- spacious, three-row interior, capability and amenities, including standard leather seats and three-zone climate control -- with the two most expensive hybrids on the market, which are cars from Lexus.

The 2008 Lexus GS 450h sedan starts at $55,665 for a five-passenger car with V-6 mated to an electric motor system for 292 horsepower. The 2008 Lexus LS 600h L sedan has a V-8 with electric motor system developing 438 horsepower. But the starting retail price is more than double that of the SUV hybrids at $104,765.

Just don't expect high-flying gasoline mileage from the Tahoe and Yukon Hybrids.

Not surprisingly, their four-wheel-drive versions like the one I tested are dead last in government fuel ratings among hybrids at 20 miles per gallon in both city and highway travel.

But these are vehicles weighing more than 5,600 pounds, and without the hybrid electric assist system, they'd carry ratings of only 14/19 mpg for city/highway driving. Thus the 20-mpg rating in city driving amounts to a 42 percent rating improvement.

If only I had managed to get 20 mpg during my test drive. Even in virtually all city driving, I racked up 16.4 mpg in the test Tahoe Hybrid.

I was thankful the vehicle didn't call for premium gasoline to fill the big, 24.5-gallon tank. As it was, a fill-up of regular fuel could run to $75.

I also didn't enjoy the respect and thumbs-up that other hybrid drivers sometimes get from environmentally aware roadway colleagues. Some of the usually slow-driving, watch-the-gas-gauge Prius drivers raced to get out from behind the big, blocky Tahoe Hybrid and get in front. And this was despite the fact the test Tahoe had eight badges of various sizes on it denoting it was a "hybrid."

The badges weren't the only signs that this Tahoe was different.

The front air dam goes down lower to the pavement than on regular Tahoes, and standard side running boards are aerodynamically shaped. Both details, plus a slightly revised rear end treatment, help smooth airflow around the vehicle for improved gas mileage.

Still, the Tahoe in hybrid form keeps its sizable girth and nearly 17 feet of length for excellent interior shoulder room, headroom and legroom. Passengers in both front and second rows have at least 40 inches of legroom, and people in the third row get more than 38 inches of headroom.

When second and third rows aren't in use, the Tahoe Hybrid offers a commodious 108.9 cubic feet of cargo space.

Road bumps in the test vehicle were deftly handled with little fuss coming through to passengers, and the interior was quiet and serene.

Engine sounds were confident and pleasing during acceleration, and the electric ratio hybrid transmission worked smoothly.

Note that the V-8 has Active Fuel Management which automatically adjusts the number of engine cylinders in use -- four or eight -- to match driver needs and maximize fuel economy. This was done so imperceptibly, I never noticed the changes.

But I did hear some electric sounds, like a whirring tone that came on as the Tahoe Hybrid would start up. This sound would be masked as the V-8 came on to join the initial electric power and then it would return as the V-8 automatically turned off when the Tahoe Hybrid slowed to a stop.

There was nothing wrong, but these normal hybrid sounds took a bit of getting used to.

The mass of the Tahoe Hybrid was evident as passengers and I felt the weight shift from one corner of the vehicle to another in twists and turns. And sometimes, I wished for stronger brakes, because there's an awful lot of mass that needs to be stopped in this vehicle.

Steering also had a lazy feel.

All safety equipment is standard on these hybrid SUVs and include electronic stability control, head curtain air bags and OnStar, an emergency notification service.

Non-hybrid 2008 Tahoes and Yukons earned across-the-board five out of five stars in government crash tests. According to Consumer Reports, reliability of the gas-only Tahoe has dropped to well below average.