2006 Ford Explorer Chassis
2006 EXPLORER IS MOST CAPABLE EXPLORER EVER
For 15 years, the Ford Explorer has been first in combining capability and refinement. Now, the segment benchmark is set even higher, as the 2006 Explorer features an all-new frame, new independent front and rear suspensions, a revised steering system and improved payload and towing ratings.
"When you combine all of the improvements to ride, handling, towing and payload, the 2006 Ford Explorer really is the most capable Explorer ever," says Judy Curran, Explorer chief engineer.
Body-on-frame construction, tested to F-Series Super Duty standards
According to Raj Nair, SUV and Body-on-Frame Vehicles executive director, the key to the Explorer's capability is its body-on-frame construction:
"One of the distinct advantages of a body-on-frame vehicle is its ability to isolate the passenger compartment from broken roads. This isolation is even more noticeable during more strenuous driving activities, such as towing and off-roading."
The difference is also apparent in Ford Motor Company's internal testing.
"Body-on-frame SUVs like the Ford Explorer are tested to the same off-road and towing standards of Ford trucks," says Nair. "The tests were originally designed for F-350 owners, most of whom use their trucks exclusively for towing. Not many Explorer owners will use their trucks to that extent, but our tests verify that the Explorer is capable of whatever its owner needs to do-as a full-time tow vehicle or just pulling a camping trailer for the weekend."
The durability these tests validate is evident in the experience of many Explorer owners, including Scott Douglas. Douglas, with the support of Ford Truck Motorsports, won the 2004 Best of the Desert off-road racing championship in the Pure Stock class. Douglas's 2002 Explorer 4.0 proved to be virtually unstoppable, winning four out of five races, using a stock frame, stock body panels and stock suspension components — including the independent rear suspension.
Scott Douglas won the 2004 Best in the Desert off-road racing championship for the Pure Stock Mini SUV class in a 2002 Ford Explorer 4.0.
All-new, tube-through-tube frame is up to 63 percent stiffer, inspired by F-150
The 2006 Explorer features an all-new frame that is better in all significant measures: It's more rigid, safer and more capable than ever before.
Extensive computer-aided engineering (CAE) modeling enabled engineers to add strength where it was needed. For example, the new frame rails feature taller and wider sections than before. In crucial areas, the sections are also thicker for additional strength where it's needed, without added extra weight where it's not.
Explorer features a robust tube-through-tube frame construction, where cross members pass through the primary frame rails.
Possibly the most significant change was moving from traditional flat joints — with the cross beams attached to the top of the frame rails — to box joints. The Explorer adopts the F-150's tube-through-tube frame design, where the cross beams pass through the frame-rails, creating an inherently stronger joint. These joints are then completely welded around the perimeter.
As a result, the Explorer frame boasts a 55 percent increase in torsional stiffness, and a 63 percent increase in bending resistance, improving ride and handling. The stiffer frame also helps eliminate squeaks and rattles in the cabin, improving long-term customer satisfaction.
Explorer's stiffer frame delivers improved handling, and decreased interior noise, even over rough, uneven roads.
"One of the easiest ways to detect frame flex is noise in the cabin," says Curran. "As the frame moves, it causes body panels and trim pieces to squeak and rattle as they shift position. Thanks in large part to the new frame, the 2006 Explorer is remarkably quiet, even on our toughest off-road washboard tests and four-post shaker tests."
The frame also plays a key role in the Explorer's impressive safety package. The front crush rails are three inches longer than before, providing even more energy absorption during front or offset-front crashes to further enhance occupant protection.
New suspension attachment points up to 593 percent stiffer, body mount attachment points up to 169 percent stiffer for improved NVH
In addition, the 2006 Explorer features all new body and suspension mounts. These brackets also benefited from extensive CAE modeling, adding strength without adding unnecessary weight. As a result, the mounts are significantly stiffer, up to 593 percent, when measured on the redesigned frame.
Many of the body and suspension attachment points are manufactured with a post-piercing technique. Instead of pre-drilling the holes before assembly, with post-piercing the brackets are mounted to the frame and then the holes are pierced.
"Before, the holes had to be made larger than necessary to compensate for manufacturing variances," says Todd Hoevener, Explorer vehicle engineering manager. "These variances in the frame could add up to six millimeters in total. By mounting the bracket and then punching the hole, we have taken most of that variance out of the equation. In fact, some tolerances have decreased as much as 50 percent. This provides much better build quality, with consistent fit and finish and fewer long-term squeaks and rattles."
A pair of rubber balls demonstrates Explorer's new body mounts, which improve road isolation. The butyl rubber ball has very little rebound compared to the natural rubber ball.
New body mounts were also used to improve the overall of the 2006 Explorer. The new, softer mounts feature butyl rubber for improved damping and tuning. The stiffer frame and softer body mounts help isolate road inputs before they can reach the passenger compartment.
"Before, the majority of our body mounts were natural rubber," says Lucy Yuen, Explorer NVH supervisor. "Where appropriate, we've used new mounts made of butyl rubber to help dampen impacts, rather than bounce on impact. We use a pair of rubber golf balls to illustrate the difference: They look and feel identical until you drop them: From six to eight inches, the natural rubber ball will bounce eight, nine, maybe 10 times but the butyl rubber ball doesn't bounce once."
According to Yuen, this new butyl rubber allowed the NVH engineering team to help isolate road impacts transmitted into the cabin. This, in turn, allowed the chassis dynamics team to provide a firmer suspension tuning, for improved handling without sacrificing ride comfort.
All-new IRS, revised suspension tuning takes advantage of
"Although we feel the Explorer already offered the best driving experience in the segment, the new frame and improved attachment points created a tremendous opportunity to improve the ride quality," says Curran. "To take full advantage of the increased stiffness and improved ride isolation, we designed a new independent rear suspension assembly, new monotube front suspension, and a new steering system."
The 2002 Ford Explorer was one of the first SUVs in the industry to offer an independent rear suspension (IRS), and to this day is one of the only body-on-frame SUVs to offer the refined driving dynamics of IRS.
In addition to the ride and handling benefits of allowing each wheel to move independently, IRS offers the advantage of better packaging. With shorter shock towers than a live-axle setup, it enables more interior room to be dedicated to cargo and people. As with the 2002 model, the 2006 Explorer also offers the industry's only porthole-in-frame design, passing the IRS halfshafts through the frame rail. This lowers the IRS assembly even further, providing a lower center of gravity for improved handling, and enabling Explorer's exemplary third-row accommodations.
For 2006, the short- and long-arm design is replaced by a trailing arm design. The new design is more robust than before to increase capacity, but also delivers better ride comfort.
The 2006 Ford Explorer features an all-new independent rear suspension and delivers exemplary ride and handling as well as improved third-row occupant space.
"The driving factor for changing to a trailing-arm setup was ride smoothness without any sacrifice to body control," says Hoevener. "Because the frame stiffness increased so dramatically, we wanted to do more than simply retune the shocks and springs of the existing IRS."
The front suspension has also been redesigned to take advantage of improvements in the new frame. The front retains its short-long-arm, coil-over-shock design. However, the stamped-steel upper and lower control arms are all new, with a lighter, stronger design.
Both front and rear suspension assemblies incorporate new monotube shocks (replacing twin-tube shocks), again to take advantage of the new road isolation and frame stiffness. The monotube shocks are tuned to deliver softer reaction to impacts — such as potholes and expansion joints — while providing confident body control over larger road undulations and under cornering.
Improved brakes contribute to improved payload, 7,300-lb. towing capacity
With the stronger frame and more robust suspension design, upgrades to the brake system enabled a 10 percent increase in payload, and a 7,300-lb. towing capacity.
The system retains sizeable front and rear discs: 305 x 30-millimeter vented front discs, and 301 x 12-millimeter solid rear discs. The front two-piston calipers grew from 46 to 51 millimeters, and the caliper housings are stronger for less flex under full brake pressure. The pad thickness also has increased and the pad area has gone up in proportion to the increase in caliper size. This provides increased braking effectiveness for increased payload and towing capacity.
The 2006 Ford Explorer's brake system has been redesigned for increased durability, contributing to Explorer's increased capability.
As a result, the 2006 Explorer boasts up to a 10 percent increase in payload, or:
Towing is similarly improved, with maximum towing capacity increased from 7,140 pounds to 7,300 pounds.
- A 4x2 five-passenger V-6-equipped model, at 1,520 pounds
- A 4x2 seven-passenger V-6-equipped model, at 1,460 pounds
- A 4x2 five-passenger V-8-equipped model, at 1,520 pounds
- A 4x2 seven-passenger V-8-equipped model, at 1,460 pounds
- A 4x4 five-passenger V-6-equipped model, at 1,510 pounds
"It was essential that we kept the current Explorer's confident towing manners," says Curran. "You want to make sure the Explorer is in control of the trailer, not the other way around. A significant amount of chassis testing was done to validate that the Explorer's suspension, powertrain, and braking systems are confident and composed, even when pulling a trailer that weighs almost 3,000 pounds more than the truck."
Contributing to the confident nature of the Explorer is the standard four-wheel, three-channel antilock braking system (ABS) with electronic brake force distribution (EBD). The ABS controls the front wheels independently and the rear wheels in tandem during heavy braking to improve vehicle control.
Explorer's new chassis delivers extremely confident towing manners, as well as up to 7,300-lb. towing capability.
The ABS with EBD employs dynamic proportioning, measuring braking force versus traction and allocating brake pressure to the wheels that have the best grip even before the ABS system kicks in. This helps reduce the braking distance. Explorer's exemplary braking system, paired with standard AdvanceTrac® with Roll Stability Control, offer a comprehensive active safety system to help prevent accidents from occurring.
Revised steering system, available 18-inch wheels complete
The front end also benefits from a revised steering gear, with a "drooping flow" pump. This reduces steering efforts at parking-lot speeds by as much as 15 percent. However, as the speeds increase, the steering system automatically decreases assistance, for a firm, confident feel on the freeway.
"The steering is really remarkable," says Curran. "It's nice and light at low speeds, making the 2006 Explorer very easy to maneuver in and out of parking spaces. Yet, you don't want light steering efforts at highway speeds, as that can cause drivers to input steering changes they didn't really want. The Explorer's new system offers a nice, firm, confident feel at speed that tracks straight and true."
The steering system also benefits from improved mounting brackets and the revised front suspension. As a result, tactile vibration felt through the steering wheel has decreased by 35 percent.
Finally, the 2006 Explorer is available with six unique wheels and three tire sizes, including the first 18-inch package offered on Explorer:
Changes result in new standards for SUV driving dynamics
- P235/70R-16 all-season tires with 16-inch styled steel or machined aluminum wheels
- P245/65R-17 all-terrain tires with 17-inch machined aluminum, painted aluminum, or chrome-finished aluminum wheels
- P235/65R-18 all-season tires with 18-inch chromed wheels
According to Nair, the chassis improvements make the 2006 Explorer the new standard for SUV driving dynamics:
"Some competitive vehicles are a bit sloppy at the initial input, and then try to play catch up. Others are too quick at the initial input, and then slow their reactions down. The Explorer is very linear in response and body control, resulting in a confident, easy-to-drive character," says Nair.
With an all-new chassis and more powerful V-8 powertrain, the 2006 Ford Explorer delivers one of the best driving experiences its class.
"It's very quiet, refined, and confident over all road surfaces, even over broken pavement and during cornering. The new Explorer has good driving manners throughout the dynamic range."