Flexstasy: BDS Four Link Suspension for the Ford Super DutyPosted in How To: Suspension Brakes on January 1, 2011 0) (
Pickup truck fans were riveted when Ford trotted out the 2008 Super Duty. Compared to its predecessor, there were numerous changes to the vehicle that included a bold new exterior look with a 4-inch-taller hood height. Under the rig, the front coil spring/radius arm suspension was tweaked for better steering feel, improved braking, and a reduced turning circle. Out back, the rig got a new rear leaf spring suspension with 8-inch-longer leaves. The result was a pickup that was incredibly refined but notably rugged. It was so good that it won our 2008 Four Wheeler Pickup Truck of the Year competition.
As is often the case in the truck world, the aftermarket has found ways to make this great truck even better. BDS Suspension, based in Coldwater, Michigan, offers a variety of kits for the 2008-'10 Super Duty F-250/F-350 ranging from 1- to 8-inch lifts. One of those kits is this 4-inch system we installed, which replaces the factory radius arms with a four-link system. Why would you want this? Two words: wheel travel.
Glen Hard, BDS engineering manager, says, "Our goal was to maximize wheel travel and increase off-road performance while maintaining the vehicles street mannerisms." In addition to the increase in wheel travel, BDS notes that replacing the radius arms with a four-link system dramatically reduces caster change through wheel travel. This translates to reduced steering wheel feedback during high speed off-road maneuvers as well as reduced coil bow created by the swinging arch of a radius arm. "We replaced a single boxed arm with two massive DOM control arms that not only slide nicely over rocks, but also distribute the forces created while off-roading," Hard notes.
This particular kit was installed by the folks at Attitude Performance in Arlington Heights, Illinois, on a customer's vehicle. Technician Blake Vanderheyden completed the install, which was straightforward and harbored no nasty surprises. Here's an overview of the major components of the BDS four-link kit and how they install.
The owner of this rig replaced the stock LT275/70R18 (32.1-inch-diameter) Continental Contitrac TR tires with 35x12.50/20 Nitto Trail Grappler M/Ts. Combined with the lift, the Super Duty gained approximately 5 1/2 inches of front air dam-to-ground height (16 1/4 inches to 21 3/4 inches) and approximately 1 3/4 inches of trailer hitch-to-ground height (20 1/4 inches to 22 inches). Approach angle improved by approximately seven degrees and departure angle improved by approximately four degrees. Even though the new four-link brackets hang down approximately 2 1/2 inches further than the stock radius arm brackets, the bracket-to-ground measurement improved by approximately 3 1/4 inches.
The even bigger story was on the RTI ramp. In stock form, the 137-inch-wheelbase Super Duty climbed 58 inches up our 20-degree ramp to earn a score of 423 points. After the BDS four-link install, the Super Duty climbed an impressive 79 1/2 inches up the ramp (with the sway bar connected) to earn a score of 580 points. This 21 1/2-inch improvement on the RTI ramp shows just how well the BDS kit frees up front wheel travel.
We tagged along on a brief test drive of the Super Duty and were impressed at how well the truck drove on the paved road. The front end was smooth and stable, and it tracked very well. BDS says with 10 inches of front wheel travel, there's less than one degree of caster change, thus it's easy to understand why this translates to outstanding steering control over rough terrain.
At the time of print, the kit we installed was advertised on the BDS website for an MSRP of $2,133.83. The same kit with new rear leaf springs has an MSRP of $2,934.89.