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Conversion Factor

Originally Published in Trailer Life Magazine

Taking a road trip through beautiful country ranks right at the top of our list of favorite activities, and it’s made even more memorable behind the wheel of a capable rig. After spending some time with the 2006 Ford F-450 Super Duty, we found that maybe it is all about getting there. Equipped with a custom stretched and modified bed and riding on an innovative trailing-arm air-ride suspension, the engineers and craftsmen at AccuBuilt have taken an already proven truck and designed a first-class hauler that will get you to your destination in luxury and style, and with a big ‘ol smile on your face.

The Super Duty Ford, called upon to tow the Denali 31RG-BS fifth-wheel from Dutchmen, arrived in Crew Cab form with the highly desirable Lariat trim package. The leather-appointed power captains’ chairs, fully adjustable pedals ($120), six CD in-dash player, factory in-dash brake controller ($230), automatic climate control, polished 191?2-inch wheels and the free, yes free, front license-plate bracket belie its utilitarian heritage as a Class IV truck and rivals an upper-end SUV interior — judging by the truck enthusiasts we met.

Equipped with the optional ($4,950) turbocharged Power Stroke 6.0-liter diesel spinning the optional ($1,490) five-speed Torqshift transmission, the combination proved to be a pricey package to be sure, but after a stint behind the wheel, drivers will be easily convinced to add them to your order form. Ford gets an A-plus thanks in part to the Electronic Variable Response Turbocharger (EVRT), providing tailored boost for changing conditions or instant backpressure-style engine braking, monitored from a new boost gauge in the dash. Combine the available 325 hp with the five-speed TorqShift transmission’s ability to delay upshifts and control engine braking when the pedal is depressed in tow/haul mode, and it’s easy to see why Ford is making heavy towing easier than ever before. We were impressed with the F-450’s ability to haul the 9,960-pound Denali with acceleration available at any time, in any gear.

Ford did its homework, creating a quiet cabin that complements the leather appointments, and it was a constant surprise to hear the effectiveness of the soundproofing effort when stepping in and out of the running truck. A 68-decibel-interior sound level was common at freeway cruising speeds while towing, allowing music and conversation at its liveliest. A complete white-faced gauge package is provided. Rear seating in the dimensionally larger cab is typical fold-down bench-style, but with slightly more legroom than in front.


AccuBuilt developed a complete custom bed and rear air-suspension package for the as-delivered empty-frame F-450/550 series. The company utilizes 17-gauge Ford bed panels modified with laser cutters and die-stamp tooling to produce a stock-appearing pickup-style bed that fits tight to the cab, is heavily reinforced and is stretched approximately 3-1/2 inches to properly cover the rear wheels. The completed bed is corrosion-coated before being prepped for paint and spray-in bed liner, and before its installation, the stock fuel tank is replaced by an inline 50-gallon unit.

Bed side-rail height is slightly taller than other custom beds to maintain the factory body line look (which could be an issue when towing some fifth-wheels). This feature frees up space to carry a spare tire on the frame. The AccuBuilt rail height may be too high (although only by a few inches) to clear the “cabover” structure on those fifth-wheels featuring a flat floor up front. In many cases, the pin box can be adjusted to provide the additional clearance, but that may rake the front of the trailer when hitched. AccuBuilt has the engineering capability to optionally lower the bed-rail height but, in doing so, the truck would not retain its OEM appearance.

A simple but hidden fold-down, recessed or running board-style body step for easier access to bed contents or hitch connections would be handy.

The heart of the rear suspension is Reyco-Granning’s Maxi-Air trailing arm design that is said to be 30 percent lighter than the stock leaf springs it replaces. Two heavy-duty beams attach to the forward stock leaf-spring mounts, axle perches, rub-plate brackets and frame bracket securing the air bags between the spring beams and frame. Should an air bag fail, the dash-mounted low-pressure alarm will light and sound as the deflating system comes to rest on rubber jounce bumpers mounted inside the bag. This allows slow, careful travel to the nearest repair facility or any Ford medium-duty-truck repair location.

The automatic ride-height system utilizes a mechanical linkage between the bed and air valves, eliminating manual compressor adjustment. This system also provides a “kneeling” feature that allows air to be dumped, lowering the bed for easy hitching and loading/unloading of cargo, ATVs, motorcycles. With the bed kneeled, the Denali was quickly hitched, with better driver visibility over the tall rear seatbacks. When the suspension is re-inflated to normal ride height, it allows easier retraction of the landing jacks, and is useful with gooseneck hitches. System condensation is exhausted through “spitter” valves, with every brake activation causing a soft pneumatic hiss alerting you that the system is indeed functioning as designed.

The entire system has been engineered and built to stringent Ford-truck-quality standards using stock mounting points, pinion angles and axle-clamp integrity. Originally destined as standard factory equipment specifically for the F-450/550 platform, Ford opted not to include this package in its factory offerings, allowing AccuBuilt to step in and provide a complete Super Duty customization program.

The resulting ride with this system is compelling. We subjected the system to a variety of road surfaces, conditions and speeds to seek out its Achilles heel, but found it handled all but the worst conditions with a superior and stable ride. According to AccuBuilt project engineer Chris Smith, “The suspension system is so stable that the (factory) rear stabilizer bar may be removed without notable difference.” Crowned road surfaces and emergency shoulder separations had little effect on stability even during simulated emergency lane changes. We dubbed it a “sedan-quality ride,” but in a medium-duty tow chassis.

The basic AccuBuilt package adds $9,281 for custom bed, fuel tank, spare tire, step bumper, bed lining and custom-molded splash guards. AccuBuilt options include the air-ride suspension ($3,599), painted front and rear fender protectors ($620), body graphics ($472), Chrome package and grille ($1,564), painted front bug shield ($266), RV tailgate ($679), 30,000-pound fifth-wheel hitch ($1,853) and 17,000-pound hitch receiver ($620). These additional options brought the AccuBuilt total to $19,054, and the combined vehicle cost to an msrp of $66,214. Retrofitting is available for earlier year F-450/550s.

Full-Time Features in a Mid-Profile Body

The Dutchmen Denali is Thor Industry’s step-up laminated side-wall line of fifth-wheels and travel trailers. The 31RG-BS is its 35-foot rear-galley model equipped with its most popular three-slide floorplan, one of which provides increased walk-around space in the master suite. The ability to add the bed slide was the result of a redesigned front cap that’s 5 inches higher than previous Denali models, yet kept almost 6 inches lower than many high-profile models. This provides additional space in the cap to add more clothing storage, a swing-out TV platform and 5 feet of closet with mirrored sliders. Additional storage is still available in the traditional under-bed pedestal. The extra space realized from the redesigned bed slide also allows for a larger vanity and sink area, creating a true master suite with proper stand-up room for dressing.

The raised galley is another focal point of this rig. Buyers have a choice of booth dinette seating, or a more traditional and optional ($375) free-standing table and four chairs, as the test unit was equipped. The curbside slide was large enough to take advantage of the free-standing dining furniture, yet nicely proportioned to stow within the confines of the slide for travel. One feature we enjoyed was the addition of a small breakfast bar with two stools.

The galley has a residential feel and look to it, with large counter space stretching along half of the rear and streetside walls. Dutchmen chose to install the sink directly in front of the breakfast bar, hampering serving or working space for bar users. We would have chosen to place it on the rear wall closer to the larger optional ($225) refrigerator. A new optional ($225) hybrid convection/microwave oven has been added to the galley-appliance lineup, combining both cooking methods and effectively reducing cooking times by 50 percent.

Earth-tone fabrics have become a desirable RV décor once again, and our model was tastefully decorated in the Howland Taupe scheme with free-standing executive chairs and ottomans positioned in front of the bigger bay windows offered for 2006.

The optional window tint ($225) and the day/night shades, once an option, have become standard equipment, adding to the growing list of full-timer features in this mid-profile model.

Outside, the clean lines of the nicely appointed unit are broken only by the three slides; two are directly above the wheels, requiring modification to the plastic wheel-well flares to allow proper slide extension. As per common practice, the flares had simply been cut in two, with one half mounted to the slide and the other to the fixed part of the body. Unfortunately, neither was tightly matched, leaving crude, unsightly and sharp sawn edges on both sides of the rig. We also discovered that the housing for the shorepower cord plug, which was screwed to the body, stripped out in our hands while attaching the cord the first time.
Despite some correctable deficiencies, the Denali 31RG-BS is a rig that can be turned into a cozy full-timer with its many amenities catering to extended use. Its popular floorplan should continue to attract those looking to trade up to a laminated side wall rig but still want to retain the popular mid-profile stance.

AccuBuilt Trucks, (888) 324-7895, accubuilttrucks.com

Dutchmen Manufacturing Inc., (574) 534-1224, dutchmenmfg.com



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