Ridetech offers the 4 link rear suspension in a parallel style. Very similar in construction to the tri link…R-Joints, heavy tubing, lasercut bracketry… but the parallel 4 link uses a panhard bar to position the rear axle side to side.
In many applications, such as late model trucks, this configuration avoids interference between the upper bars and the oem gas tank. The parallel 4 link is also slightly easier for the casual installer to visualize and install because there are fewer bar mounts to deal with… the frame brackets and axle brackets carry both upper and lower bars. The parallel 4Link is available separately, with airsprings and weld-on bracketry, with bolt-on rear mounted airspring brackets, or with ShockWaves. Now Includes R-Joints!
What’s the difference between a triangulated 4 link and a parallel 4 link?
Both styles of 4 link accomplish the same thing… very simply, they hold the rear axle in the vehicle. The function of a 4 link is to keep the rear axle in its proper place under the vehicle. The bottom 2 links keep the axle in place front to back. The upper 2 links keep the axle from rotating, keeping the pinion angle as constant as possible.
On a triangulated 4 link the uppers bars are placed at an angle to the lowers. When connected securely to the axle and the frame they form a “triangle”. This is what keeps the rear axle centered under the vehicle.
On a parallel style, a “panhard bar” must be used. It runs horizontally across the vehicle connecting the axle to the frame, allowing only up and down movement. Although there are several theories as to which is “better”, in the real world it comes down to available space and preference. A parallel 4 link fits most trucks better because the fuel tank is usually right in front of the axle, inboard of the frame. A parallel is sometimes easier to install because the link bar frame mount is one piece instead of two… less time in placing and welding the upper bar mounts. But a parallel 4 link requires a panhard bar which adds slightly to the expense and can use up valuable space needed for the exhaust system. A panhard bar will also induce a small amount of side to side movement during suspension travel… not enough to feel but it may concern the customer who has an extremely tight tire to fender clearance. With a parallel 4 link you are locked into a sideframe link position… with a triangulated 4 link the lower links can be placed beside the frame or under the frame for clearance purposes.
Either system is very straight forward to install. You will spend more time with the tape measure than the saw or welder. All else being equal, for the absolute rookie, the parallel may be a bit easier to visualize and understand during installation.
Triangulated 4 link (vs. parallel 4 link)
*NO side to side movement at all… you can run tighter tire to fender clearance
*Less hardware to buy and install (no panhard bar)
*Allows flexibility in bar placement to avoid obstacles
*Angled upper bars can interfere with exhaust
*Angled upper bars can interfere with fuel tank on late model trucks
*4 more attachment points to plot and install (parallel has bar mounts built together)
Why should I put a 4 link under my car? What will a 4 link do better than a leafspring?
In a leafspring suspension, the leafs perform 2 functions. First, they hold the
rear axle in the car. They prevent both forward and aft movement and minimize pinion angle change during suspension travel. Secondly, while they are doing this, they also support the load of the vehicle. For an OEM vehicle that has had thousands of hours of development time behind it, and that will operate within a predictable range of suspension travel, leafsprings do a very adequate job. The problem occurs when the operating envelope is changed… lower ride height, more horsepower, different weight distribution, maybe a trailer… its called hotrodding! The leafsprings cannot be expected to perform as intended if the operating parameters are changed.