Will bigger prove to be better?

The ’02 GMC Envoy and Chevrolet TrailBlazer now in showrooms, which seat five with two rows of seats, will be joined in March by stretched versions that seat seven with three rows of seats.

While the ’02 Ford Explorer/Mercury Mountaineer now in showrooms will have had several months’ lead on GM with midsize sport-utility vehicles with three rows of seats–and three rows of seats appear to have the same magical, mystical attraction as the cupholder did in the ’90s–GM’s wait looks like it may pay dividends.

The stretched SUVs will be called the Envoy XL and the TrailBlazer EXT. The XL/EXT are built on 129-inch wheelbases and are 207.6 inches long overall. That compares with 113-inch wheelbases and 191.6-inch overall lengths on the midsize Envoy and TrailBlazer.

Before you ask, the Chevy Tahoe/GMC Yukon full-size SUVs are built on 116-inch wheelbases and are 198.9 inches long. Where Tahoe/Yukon gain on XL/EXT is that they are wider (76.3 inches versus 74.7 inches) and taller (78.9 versus 74.9 inches)

Most of the stretch is in the middle of the vehicles to keep from positioning seats over the rear wheels to prevent ride harshness for passengers and to ensure protruding wheel wells don’t block entry or exit from the back seats, said Jeanne Brooks, assistant brand manager for Envoy.

At a mini preview–look but don’t drive–of the GMC Envoy XL this summer (the TrailBlazer EXT was not shown), the dimension that stood out was the 3-inch-high bulge in the roof directly over the third seat.

Most SUVs offering three rows designate row three for kids because there’s not enough head room for adults. XL/EXT have surprisingly ample head room, not to mention leg and arm room in the third row. The third seat holds two adults–up to 6 feet 2 inches and 200 pounds–comfortably, GM says.

To camouflage that bulge in the roof, the XL/EXT use a luggage rack.

To get in the third row, pull a lever on the second row of seats and the seats fold and flip to provide a wide aisle. Once seated, pull another lever from the third row and the second row seat goes back into place.

Another gripe when three rows of seats are added in an SUV is that the third seat takes away cargo room behind it. In the Explorer, for example, it’s snug for luggage or clubs behind the third seat.

The XL has good cargo room. If you need more cargo than passengers, the third seat flips and folds. There’s also a convenience compartment in the floor. Open the lid and there are three compartments to hold things, including one for wet items such as swimsuits or boots.

Also, a flat panel on the cargo floor lifts up to serve as a cargo shelf that can be positioned at various heights to store items on it/below it.

While the midsize and stretched Envoy/TrailBlazer differ in size, the powertrain stays the same, the 4.2-liter, 270-horsepower V-6. The 4.2 is rated at 16 m.p.g. ci ty/21 m.p.g. highway in the Envoy/TrailBlazer. No rating as yet, but it won’t be that high in the XL or EXT. How to compensate for lower mileage? XL and EXT will have 28-gallon fuel tanks to extend driving range from the 18-gallon tanks in Envoy and TrailBlazer.

With the larger size, one item XL and EXT could use, but don’t offer, is power adjustable gas/brake pedals. Stay tuned.

And with the larger size, some are questioning the need for an Envoy XL and TrailBlazer EXT and a Yukon/Tahoe, especially with GM intent on reducing excess production and trimming the number of model offerings.

Tony DiSalle, Envoy brand manager, said GMC intends to keep Yukon even after the bigger Envoy XL arrives because in private research clinics, consumers still equate Yukon with more size and room. And, for good reason: Even with a third seat, the Envoy XL will hold seven people; a Yukon XL can hold eight to nine.

DiSalle says he expects the three-seater to account for 60 rcent of sales.

But what about folks who opt for the XL or EXT?

“If a vehicle is going to cannibalize sales from someone, it’s better that we have a vehicle that diverts consumers to another one of our products rather than diverting them to a product from one of our competitors,” DiSalle said.

The Envoy price range is $29,000 to $34,000, and the Yukon range is $33,000 to $37,000. The TrailBlazer price range is $25,000 to $33,000, and the Tahoe range is $32,000 to $35,000. The XL/EXT will fall in between.

The XL and EXT will be offered with two- or four-wheel-drive. The TrailBlazer EXT, it will be offered only with the LT trim package, not the base LS or top-of-the-line LTZ.

The XL will be offered in the SLE or top-of-the-line SLT trim levels.