Ford F-250 - Ultimate Super Duty Part 4

01. The team at Dynatrac jumped through some serious hoops to work us into their schedule and install a prototype Pro Rock 60 front axle. If you're running the typical 35-38-inch-tall tire, this is the solution to your Super Duty's front axle problems .

02. The Pro Rock starts with an all-new Dynatrac centersection cast from nodular iron. Dynatrac says that it's 40 percent stronger than a stock Dana 60 and gives you more ground clearance than a Dana 44, without requiring modifications to the ring gear. Dynatrac installed the front ARB Air Locker and set up the Precision Gear set.

03. Dynatrac offers a kit (background) to retain your Ford Dana 50 or 60 and replace the unitized bearings. We opted to ditch the entire Dana 50 and run a complete Pro Rock 60 axle, which also gets you a new track bar, tie rod, drag link, and all associated mounting brackets. These components are key when you run massive tires and upgrade the axle.

04. The Pro Rock 60 for Super Duty trucks comes with the products you'll need so you can retain your metric bolt pattern and factory brakes with or without ABS. The off-the-shelf unit will retain the factory track width, but you can order one any width you want. We actually went 2 inches wider to help our massive meats clear the leaf springs and sheetmetal. The tires still hit, but not as bad.

05. The track bar on a lifted Super Duty is a problem. It's fairly easy to bend the factory bar, but a beefier bar will often rip the mount off the frame. Dynatrac's solution was to redesign the frame mount, tying it into the engine crossmember with two rods. The axle mount is incorporated into Dynatrac's passenger-side spring plate. This assembly isn't going anywhere, and the bar won't bend either...we tried.

06. The Dynatrac tie rod incorporates a dual-steering stabilizer system that's relatively protected from rocks and small cars. The U-bolts were trimmed and the front sway bar tossed for a clean underside.

07. With the frontend handled, we felt obliged to clean up the rear. Ford clamps the rear shock mounts to the housing in a way that dangles the shock about 3 inches below the bottom of the axletube. We rotated the mounts up and welded them on. We lopped off the Flowmaster exhaust tip just past the last hanger to protect it from rocks. The sway bar also hangs down so we ditched it. Trust us, you won't miss the sway bars, and the fewer anchors you have under a trail truck to catch rocks, the better.

08. The key to this truck's appearance and performance was its Michelin tires. We wanted to do something way different than the standard 35-inchers, so after considerable research, we found these Michelin XMLs in a 395/85R20 size. The XML is a military tire with a G load range (that's 9,645 pounds per tire at 95 psi). These tires are also offered in a 14.00R20 (49.5x15.1) size and 12.00R20 (44.5x12.2) for 20-inch wheels, and 325/85R16 (38.7x12.9) for a 16-inch wheel. There's a slightly less aggressive XZL also available.

09. Wheel choices in 20-inch diameter to fit a Super Duty are pretty slim. The solution came from Trailready, who makes 20-inch bead locks. These wheels are used on some Unimogs and a few extreme rock buggies. The wheels feature a huge aluminum ring attached to custom-made steel wheels.

10. Our final engine modification was to install a Holley Power Shot air filter. In addition to a massive improvement in airflow, the Power Shot filters are designed to seal to the airbox just like the original factory air filter. This is extremely important in a turbodiesel application where any dust past the filter means death to the turbo.

11. The rules that we wrote for Ultimate Adventure stated that every truck needs a minimum of a rollbar. D'oh! OK, it's a good idea for safety. We called Art Morrison Enterprises which builds awesome race-car cages and chassis and suspension components. Turns out the company was interested in offering a mail-order rollbar for these trucks anyway. They mocked up a six-point bar to fit in our four-door SuperCab and shipped it out.

12. The Art Morrison rollbar came with a main hoop, two rear-facing down bars, two door bars, and six 6x6-inch 3/16-inch steel plates. The rear seat has to go bye-bye, but that just leaves more room for storage. You didn't really want to sit back there anyway. We pulled up the carpet and spent about an hour positioning the main hoop and downbars where we wanted them. Using a vise and a sledge hammer, we bent the main-hoop plates so they would fit the floor perfectly.

13. We positioned the main hoop just behind the dome light, which puts it behind the driver's head with the seat all the way back. It should be far enough from the occupants' heads that there won't be contact during an accident. Making the bar fit with the factory seats and door panels was no easy task, but Art Morrison did a great job. If you're willing to use racing seats and seriously trim or remove the door panels, a much stronger rollbar could be constructed.

14. The final piece of the rollbar is door bars. These not only protect from side impacts involving low-flying aircraft, but they add vertical stability to the main hoop. A bar that goes straight down from the main hoop to the front floor would be stronger, but wouldn't clear the seat and door panel. The tubing is all 13/4-inch-diameter mild steel with 0.134-inch tube wall.