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Engineered Elements of the ’07 Sport Trac
While Honda is getting props for the Ridgeline, there’s another four-door out there with a composite bed to boot.
By , Editor-In-ChiefGary's BioWrite Gary

The second-generation Sport Trac.
The second-generation Sport Trac. Seats five. Has a bed on the back for gear. And you can fit it in your garage.
The second-generation Ford Sport Trac, an ’07 model, has hit the streets, so we talked with Craig Brewer, chief engineer, to get some insights on the vehicle...

  • Compared with a conventional four-door Explorer, 80% of the body parts are different. Forward of the B-pillar, the panels are the same, including the aluminum hood.
  • The independent front and rear suspension (front: short- and long-arm design with coil-over shocks and a 32-mm stabilizer bar; rear: trailing blade short-and long-arm design with coil-over shocks and 23-mm stabilizer bar) are the same as on the four-door. But given that the Sport Trac has a bed, the tuning is different.
  • The frame for the Explorer is constructed in three sections: front, middle, rear. The mid section of the Sport Trac is 16.8-in. longer than the four-door model. There is an additional cross member on the Sport Trac for lateral stiffness. (The Explorer frame picked up on an engineering design feature used for the Ford F-150 pickup, with the cross beams passing through the longitudinal frame rails. This is called “tube-through-tube.”)
  • Compared with the first-generation
  • Sport Trac’s frame, the new one offers 444% more torsional stiffness. This is primarily achieved by having gone from a C-channel design for the frame elements to one that’s fully boxed.
  • The Explorer is the first Ford application of a six-speed transmission in a rear-wheel-drive application; the six-speed is mated to a 4.6-liter, 24-valve V8. This transmission is the outcome of work that was done as a joint venture with ZF. The ZF-manufactured six-speed was first offered in a Ford product in the ’05 Lincoln Navigator. The one used in the Explorer is similar. It, however, is build at the Ford Livonia Transmission Plant. (There is also a 4-liter V6 and five-speed automatic combo available.)
  • Like the previous generation, the Sport Trac has an SMC composite box—inside and out—with the outer being painted body color and the inner a molded-in black liner. The bed consists of four panels: floor, headboard, and sides. There are three storage bins molded into the panels, one behind the headboard and two behind each wheel well. The tailgate, however, is steel. The D-pillar for the tailgate is a hydroformed, U-shaped steel beam. The hydroforming not only allows the assembly to have an overall reduced part count (8 vs. 15 for the previous design), but it also cuts 7 lb. The bed underwent testing similar to that used for the bed of an F 150, including a 55-gallon drum drop test, in which a drum is dropped onto the bed as though someone got it up onto the tailgate and then?...Oops! The box offers 37.5-ft3 of cargo capacity and can handle a 1,380-lb. load (in a 4x2 V8 configuration).
  • The vehicles benchmarked during the development of the truck include: Honda Ridgeline, Toyota Tacoma, Dodge Dakota, Nissan Frontier, and the four-door Explorer (Brewer has worked on Explorers for nine years, so that’s not surprising).
the frames for the four-door Explorer and the Sport Trac
As shown here, the frames for the four-door Explorer and the Sport Trac are fundamentally the same, with the primary difference between the two is the 16.8-in. lengthening for the Sport Trac of the mid section of the frame.
These are the elements of the interior of the SMC box on the back
These are the elements of the interior of the SMC box on the back—which, incidentally, can accommodate 4x8-ft. sheets of plywood. The D-pillar is steel, a hydroformed component.