Four-link front suspensions have many purposes. Whether you want your truck to articulate more, handle better, or increase its traction, a four-link is the way to go. As more and more folks began to hot-rod their easy-to-modify '08 to '10 Super Dutys, the radius-arm front suspension became very detrimental. Hard, four-wheel-drive launches at the dragstrip often result in so much bouncing that the front tires look like dribbling basketballs, and it gets even worse when the suspension is taxed, such as in sled pulling.
| River City Diesel’s four-link conversion was born in 2009, after big-horsepower tunes had just been released for the 6.4L Power Stroke and front wheelhop issues began to surface. For most trucks, the factory radius arms simply can’t hold the front axle stationary while sled pulling, or during boosted, four-wheel-drive launches on pavement. Each component is shot-blasted, then powdercoated semi-gloss black.
What Exactly Is A Four-Link Suspension?
A four-link suspension uses steel bars (often DOM tubing) to locate an axle under a vehicle and keep its side-to-side and front-to-back movement to a minimum-yet at the same time, allows it to travel up and down. The added travel (and articulation) provides more traction than the factory radius arms, which most performance-oriented 6.4L owners are after. In our case, we were having severe wheelhop issues with an '08 regular cab F-250 we've been testing at the dragstrip the past few months.
"We went faster without adding any horsepower."
River City's Solution
We chose to install one of the few aftermarket four-links available for stock-height trucks: River City Diesel's four-link conversion for '05-and-newer Ford Super Dutys. The company's complete bolt-on kit was exactly what we needed to settle down the Ford's tendency to excite the front end at the track. River City's high-quality system comes with durable components designed to withstand the shock load of a boosted launch and the stresses of a sled pull. With the addition of the four-link system, we picked up three-tenths of a second in the eighth-mile. And, because three-tenths equates to nearly half a second in the quarter-mile, we went from a 12-second truck to an 11-second one. We went faster without adding any horsepower, which goes to show just how efficient the four-link suspension is at controlling the axle.
How (and why) It Works
Having two bars between the frame and axle serves a very important purpose when it comes to fighting axlewrap. Once the torque load being applied to the ground overcomes the suspension's ability to keep the axle in place, the axlehousing will try to rotate the opposite way the wheels are turning. To remedy this, the four-link kit effectively loads the top arm and pulls in the bottom one.
| the Four Link Fix Ford Suspension Upgrade four Link System Installed
Getting the geometry right is the most important aspect of an aftermarket suspension. While River City Diesel's four-link system is adjustable, the company has gone to great lengths to make it work perfect-right out of the box-for your stock-height Super Duty. Its system comes preset to work on trucks lowered up to 2 inches and lifted up to 3 inches (such as with leveling kits). The only reason for adjustment would be to dial in the caster.
