“Making something like this work off-road is the easy part,” American Expedition Vehicles founder Dave Harriton admitted as we soaked in the towering FXL at a sprawling ranch property in Ojai, California. “Making it drive like a normal truck out on the street is the hard part.”
Although there's a dose of modesty built into Harriton's assertion, he's learned a thing or two about developing OEM-level refinement since AEV got its start out of a humble garage in Missoula, Montana, back in 1997. Originally focused on creating long-wheelbase Wranglers, the company quickly expanded into more comprehensive conversions with V8 swaps, truck beds, and other components that weren't on Jeep's menu at the time before bringing ¾-ton Ram pickups into the fold.
Along the way, the fledgling company secured multiple Chrysler Design Excellence Awards at Specialty Equipment Market Association (SEMA) shows, which in turn led to a direct collaboration between AEV and Jeep for several special-edition Wranglers. These days, AEV offers everything from skid plates and wheels to full suspension systems, and the company also serves as a Tier 1 supplier for Chevrolet on models like the AEV Colorado ZR2 Bison and AEV Silverado 1500 ZR2 Bison.
"That's where you start having to consider stuff that most other aftermarket companies never really have to worry about: things like crash-worthiness targets, advanced driver-assistance systems (ADAS) compatibility, and the requirements of mass production," Harriton explained. "Every bumper we make is 3D scanned to ensure it's within one millimeter of spec."
Now, AEV has turned its attention to the Blue Oval with the AEV FXL. Offered for Ford's latest F-250 and F-350 Super Duty trucks, one could rightly assume that the "XL" stands for extra-large. But Harriton was quick to point out that it's actually the Roman numerals for the number 40, as the package's massive 40-inch all-terrain tires are essentially the foundation of this conversion.
Making a tire this big work properly with the Super Duty platform was no small task, as it turns out. Harriton said that AEV tends to prioritize functionality over style, so instead of just raising the suspension to the moon in order to get the required clearance, the company focused on accommodating the tire with as little suspension lift as possible to maintain stability and preserve the payload and towing capabilities.
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They started by creating a CAD model of the tire and the Super Duty's front suspension, then ran simulations of all possible articulations, complete with bushing deflection, to identify where changes were needed. The team ended up moving the front axle back by ten millimeters and matched it with a four-inch suspension lift, specially tuned Bilstein dampers, and fender flares that are rotomolded for enhanced strength.
"Some folks think that the flare design was modeled after modern Chevys, but it was actually inspired by the seventh-generation F-Series fender," Harriton noted during a walkaround of the truck.
Combined with the FXL's 18-inch beadlock wheels and stamped-steel front and rear bumpers, the end result is a machine with a seriously formidable look. Yet the stance and tire size ultimately help even out the Super Duty's proportions. Features like the Warn winch, auxiliary lighting, and sacrificial front bumper skids on this test truck are optional, as is the graphics package.
After hoisting myself up into the driver's seat, we set off on one of the property's winding trails. AEV's conversion doesn't change anything about the Super Duty's powertrain, but with Ford's high-output 6.7-liter Power Stroke turbodiesel V8 offering 500 horsepower and 1,200 pound-feet of torque straight from the factory, it's not like the FXL is lacking for grunt.
The truck also made short work of the rocks, ruts, and stream crossings that we encountered along the way. The tires' massive sidewalls effectively acted as another bushing between the cab and the ground, adding an extra layer of compliance that proved especially useful over choppy terrain. But AEV's engineering efforts truly proved their worth on the mountain roads that we tackled later on.
While low-speed maneuvers on dirt trails can provide some insight into a truck's four-wheeling prowess, that environment tends to mask any issues with the vehicle's behavior when it's subjected to street driving. And let's be honest: even with a truck like this, most owners will spend far more time on pavement than on trails, making its on-road manners arguably more important.
Here, the triple-rate progressive springs and AEV's tweaks to the suspension geometry work in tandem to maintain ride quality that's similar to the stock setup without the wayward handling that often plagues lifted trucks with huge tires. The FXL also tracked straight on long stretches of road with minimal steering correction, a characteristic that's particularly important for a truck that's likely to see a lot of extended highway stints.
"This isn't like a heavy-duty Raptor, or something like that," Harriton added. "This is the kind of truck you'd use to bring your family out to an off-road park while hauling a couple of toys, and then take it out on the trails while you're there."
Today's heavy-duty pickups have indeed become the multitool of the truck world, combining stunning capability with a sense of civility and even hints of luxury, and the FXL really just broadens that versatility without giving up anything in the process. Well, except for a chunk of change. AEV says the FXL conversion will start at about $25,000 on top of the price of the truck and go up from there.
Although the FXL isn't offered directly from Ford like Chevrolet's AEV-badged models are, customers can order a complete truck with the FXL conversion, or buy individual components, through authorized AEV dealerships right now. The conversions carry a three-year, 36,000-mile warranty. A frame-mounted brush guard and other optional equipment will be available later this year, as will support for F-450 and F-550 models.
Images: Bradley Iger, AEV
