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The front Ford F53 kit comes with brackets and hardware and sells for $655. Labor time is about one hour.

The rear Ford F53 kit requires more brackets and takes longer to install. It sells for $695 and labor time is 1.5 hours.

The front SumoSpring installed on a Ford F53 front axle.

The rear SumoSpring installed on a Ford F53 chassis.

that can help maintain the original factory ride and improve it. The products under- went testing in extreme conditions ranging from a blistering 200 degrees Fahrenheit to a frigid minus 40 degrees F., combining heavy loads with rugged terrain in more than 18 months of trials. There’s no pos- sibility of a system failure because of leaking air, and the closed-cell urethane won’t rupture; in fact, it can be punctured without loss of performance.

INSTALLATION The company’s principals joined us for an installation session on two Class A motor - homes — one with a Ford F53 chassis and the other a Workhorse W22 series chassis. These are the most popular chassis on the market. The W22 carried a 2006 National RV 34-foot Dolphin coach, while the F53 had a 2007 Winnebago 30-foot

Sightseer mounted atop.

Kits — which were installed at both the front and rear of each coach — come complete with all mounting hardware required for installation. Existing frame holes are used as much as possible; only one 38-inch hole had to be drilled per cor- ner. The front kits are easier to install since they are out in the open. Brackets bolt to the frame and top of the SumoSprings and U-bolts attach them to the leaf springs.

The rear units mount in a similar fash- ion, but are more difficult to fit because of their cramped locations above the leaf springs just forward of the rear axle. Drilling in the tight confines consumed much of the time; removing the tires would make it easier.

Kits are generally installed by shops that do chassis work, although installation is simple enough that an agile, experienced

do-it-yourselfer should be able to tackle the task with a few hand tools and a drill, plus some heavy blocks, a hydraulic bottle jack and safety jackstands. The coach needs to be lifted high enough to just get the tires off the pavement, one end at a time.

RESULTS We drove both coaches on a test route before the installations and then we drove them after the kits were installed for comparison. We also tried out the Workhorse with just the rear kit installed, and then with both front and rears in place. On the F53, ride height increased by 112 inches at the rear, and 1 inch at the front. (Stock front suspen- sion travel, measured with the weight on the wheels, was only 2916 inches.) On the Work- horse, ride height increased marginally (only 38-inch at the rear and 18-inch at the front).

The result with both coaches was a

September 2010 l MOTORHOME

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