Cross/utility vehicles exploded for a 1.67 million-unit year in 2003, according to Ward's data.
That was a 66% hike over 2001 and a whopping 208% jump from 2000. One of every dozen vehicles now sold is a CUV.
So even those not connected to the auto industry would have difficulty missing the landslide of new CUVs on the road. Much of the popularity comes from the perception CUVs deliver the all-wheel-drive (AWD) traction and cargo-hauling capability of the SUVs that started the utility-vehicle trend — but without the bulk.
SUV Lite, if you will.
Because they are based on car-like unibody structures and components, the assumption is crossovers should be lighter and nimbler than the hulking, body-on-frame SUVs (most adapted from crude pickup trucks) that originally wiled Americans away from their limited-purpose cars.
Most CUVs are nimbler — nobody's arguing about that. But how did they all end up so heavy, and why aren't they demonstrably lighter than SUVs?
Like any of the Lite stuff American consumers love to buy, it seems reading the fine print is advisable. Tight and often-curvaceous sheet metal can convince customers CUVs are the swimsuit models of the showroom, compared with body-on-frame SUVs.
But examine the profiles on these pages, and it is evident most CUVs are no lighter — and sometimes heavier — than similar-sized “traditional” SUVs.
Although there's no absolute consensus, auto maker and supplier engineers say they aren't surprised the unibody CUVs unleashed so far haven't proven to be shrines of mass reduction. Why? Because you can have it big or you can have it light.
First, most CUVs are bigger than they look. And that means added weight.
Jim Federico, General Motors Corp. chief engineer-Prestige Vehicles, offers the Cadillac SRX as an example.
The SRX's 116-in. (295-cm) wheelbase is exceptionally long: 3 ins. (8 cm) longer than a Chevrolet TrailBlazer and 4 ins. (10 cm) longer overall — although it doesn't appear that way when the two vehicles are viewed side-by-side.
“We decided to put a third-row seat back there — and when you have that kind of wheelbase, you have to have a lot of structure,” says Federico.
Engineers like to use the terms “structure” and “weight” interchangeably because that's the cold fact. Moreover, Federico says unibody construction sometimes works against a longer-wheelbase vehicle because “you have front and rear subframes that aren't connected by a frame. That means you need more structure.”
Larry Dominique, chief product specialist-trucks for Nissan North America Inc., agrees the size of current CUVs makes for compromises of unibody weight advantages.
“Most of the time, you have to overdesign the suspension of a unibody (CUV),” says Dominique. “And as you start to build up these pieces, you'll notice there's not a lot of difference between the unibody and the body-on-frame.
“Look at the (Volkswagen) Touareg,” he continues. Touareg, at 5,086 lbs. (2,308 kg) in V-6 form, is the poster child for CUV bloat — yet most competing engineers admit a high regard for its engineering purity of purpose.
“It's obvious they ‘baked in’ a lot of performance in the suspension,” Dominique says. “That means weight.”
Dominique observes early crossovers such as the Honda CR-V and Toyota RAV4 are derived from compact-car unibody platforms and may have created the expectation that larger CUVs would be similarly light.
Size definitely matters when it comes to weight, asserts Ken Kundrick, product technology leader-engineering group at Tower Automotive Inc., one of the world's most prolific developers and manufacturers of both ladder frames for body-on-frame trucks and SUVs, as well as multifarious chassis components for CUVs.
“When you get to a certain wheelbase, you have to really look at the tradeoffs between body-on-frame and unibody construction,” he says.
Kundrick, who's worked on frames and components for all types of vehicles, says he's far from astonished that unibody CUVs that essentially are larger than midsize SUVs are no lighter.
At Chrysler Group, there's even a basic formula to measure the “worth” of a vehicle's weight in relation to its size, says Mike Donoughe, who is vice president of the Family Vehicle Product Team that comprises minivans and the new Pacifica CUV.
Donoughe's aware of media dissing of Pacifica's portly 4,675 lbs. (2,122 kg) in AWD configuration.
Several enthusiast-magazine road tests have chastised DC for Pacifica's mass. But he points out Pacifica, derived from DC's unibody minivan architecture, is larger than any CUV in the class. And again, size comes at a price.
The company's size/weight formula multiplies overall length by width and then divides that figure by the weight. Using that equation, Donoughe says Pacifica tops many current CUVs and SUVs in justifying its weight in relation to its size (see chart, previous page).
And don't forget height, Federico says. “These (CUVs) are tall cars,” he says. “There's a lot of mass as you go up (with sheet metal).”
“The base payload rating really is no different between an SRX and an Explorer,” asserts Dominique. “To accommodate that weight or those passengers, you have to have a certain amount of interior volume.” And the “sheer area of the body panels” adds weight, too, he says.
CUVs also are being measured against an improving target, as body-on-frame SUVs are evolving into more-sophisticated and lighter vehicles.
“The analytical tools (for developing ladder frames) have gotten more precise,” says Tower's Kundrick. “There's more optimizing in our structures, and the use of higher-strength materials allows us to manage things better (without simply adding mass).”
“The weight of body-on-frame vehicles is coming down dramatically,” adds Nissan's Dominique.
“We added more cost by specifying more high-strength steels,” for Nissan's newest body-on-frame vehicle, the Titan fullsize pickup, which helped to reduce the frame's overall weight.
Dominique says newer materials and cab-mounting designs also have significantly reduced the frame weight for Nissan's all-new Pathfinder SUV.
Tower makes the Titan frame, as well as frames for Nissan's Frontier and Xterra, and Kundrick says frame technology isn't standing still.
Tower has developed all-aluminum — and aluminum/steel hybrid — frames that are significantly lighter. Cost, however, so far has kept the alloy frames from production.
Prior to his current post, GM's Federico served as assistant chief engineer for the wide-ranging GMT800 fullsize pickup program, so he knows plenty about body-on-frame advances, too.
He says the comparatively new technique of hydroforming truck/SUV frames has delivered marked weight-reduction — in some instances of more than 100 lbs. (45 kg).
Everyone agrees there's disparity in what each auto maker wanted — and designed for — in this first generation of CUVs. Nascent definitions have produced a broad spectrum of CUVs with a widely varying degree of capabilities, attributes and abilities.
And although one of the Ward's criteria for CUVs is unibody construction, it's hardly the accepted standard of definition.
A Volkswagen of America Inc. spokesman, for instance, says of the company's Touareg: “It's not really a crossover (vehicle). It's really meant to be the ultimate SUV.”
He says Touareg engineers weren't as concerned about weight because the company wanted “a great off-road car. We wanted to create a car that is one of the best, if not the best, in its class.”
Federico echoes that point, noting many of the Cadillac SRX's components were substantially enhanced to take the same beating body-on-frame SUVs are designed to absorb.
“We put it through our truck requirements,” he says. The SRX is derived from GM's Sigma platform, first used for the Cadillac CTS.
“We definitely added mass (compared with the CTS platform),” Federico says. “We beefed up the cradles (front and rear subframes) in gauge and cross-section of height. The SRX matches truck requirements for payload and off-roading.
“If I only needed to take a CTS (structure) and raise it for ground clearance, we would have had a lighter vehicle,” he says. “We've taken the right qualities from the car side — but also have a decent payload and tow fairly well.”
Dominique adds, “I think it's everything back to when you start (to develop) a vehicle.” Once the vehicle “parameters” are established, he says, “that may or may not limit your opportunities.”
Donoughe says Pacifica target customers had “high demands for NVH (noise, vibration and harshness) and refinement. That drove us.”
He says because Pacifica's “refinement signature” and safety goals were set high, it dictated weight-intensive solutions.
“It's not always axiomatic you have to add mass,” to get high levels of safety and refinement, he admits, “but things like 5-star front- and side-impact ratings don't come for nothing.”
He says factors such as premium amenities for second-row passengers “also drove weight,” and the Pacifica's standard third-row seating pushed Pacifica another 60 to 70 lbs. (27-32 kg) up the scale in comparison to an SUV with just two rows of seats.
Donoughe says Pacifica, like Cadillac's SRX, also had to pass DC's light-truck duty cycle.
As for the next generation of CUVs, everyone agrees they will deliver better-defined attributes. And “better-defined” should mean lighter, it appears.
“What a lot of companies need to do now is understand what the vehicle's going to be used for,” says Dominique.
He says planners of next-generation CUVs may back off towing and payload capacities as the company acquires a deeper understanding of who's buying CUVs — and for what purposes.
“There will be a further blurring in the consumer's mind,” he says. Dominique believes future buyers may abandon the notion they require genuine off-road ruggedness or the ability to tow heavy loads.
Once customers essentially come to grips with their own requirements, “they won't be as concerned with what's under the floor,” Dominique says.
“Everybody is SUV-happy,” laughs Federico, saying most customers currently believe they need much more off-road ability than they ever will use.
He says CUV buyers like the security of AWD and higher ground clearance, but “as we get into more (generations of) crossovers, it will be more acceptable” to scale-back off-road attributes.
“Every version we do from here will continue to be more car-like,” Federico insists. “With that, we'll be able to be lighter. Our customers probably will aim us in that direction. We're already thinking about the next version of the SRX, and we're looking to make it lighter.”
“A crossover is like a cocktail — a mixture of three or four different things,” says DC's Donoughe. “We'll see where the segment goes.”
Chrysler Group Weight Efficiency Formula
|WEIGHT (LBS.)||LENGTH (IN.)||WIDTH (IN.)||SIZE FACTOR (LENGTH X WIDTH)||EFFICIENCY* (SIZE FACTOR/WEIGHT)|
|CHRYSLER PACIFICA AWD||4,655||198.9||79.3||15,772.8||3.388|
|TOYOTA HIGHLANDER AWD||3,935||184.6||71.9||13,272.7||3.373|
|HYUNDAI SANTE FE AWD||3,946||177.2||72.7||12,882.4||3.265|
|LEXUS RX 330 AWD||4,065||186.2||72.6||13,518.1||3.325|
|CADILLAC SRX AWD||4,320||194.9||72.6||14,149.7||3.275|
|ACURA MDX 4WD||4,451||188.7||77.0||14,529.9||3.264|
|FORD EXPLORER 4WD||4,374||189.5||72.1||13,663.0||3.124|
|CHEVY TAHOE 4WD||5,050||198.8||78.8||15,665.4||3.102|
|BMW X5 AWD||4,652||183.7||73.7||13,538.7||2.910|
|VOLKSWAGEN TOUAREG 4WD||5,086||187.2||75.9||14,208.5||2.794|
|*larger number equals greater efficiency in relation to vehicle size. Source: Chrysler Group|