There are almost as many types of 4x4 suspension lifts available as crawfish in the Chattahoochee River. Some are highly technical, and some are easy to install. Choosing a suspension system or lift is usually based on a number of factors, but these days we are finding that this decision is not just based on performance, but also economics.
We decided to revisit an economical, functional suspension lift that's relatively easy to install, the shackle flip. There are two types of shackles, tension and compression, and both have pros and cons. We installed a 4-inch Offroad Design shackle flip kit on an older Chevy 4x4 and, in just a couple hours, were able to bolt-on 35-inch tires for additional ground clearance, maintain a close to factory ride, and enhance the truck's off-road performance.
1. Offroad Designs' compression shackle flip kit comes with everything needed for a rear leaf spring lift. The advantages to a compression shackle system, aka shackle flip, is that it is typically less expensive than a set of leaf springs. A shackle flip can also retain the factory spring and load capacity, providing lift without a block. For taller lifts a spring can be used with less arch for any given lift height. The slight disadvantage of a compression shackle is that the shackle flip (shackle itself) has a limited drop effect, meaning the shackle doesn't drop (lower) the back of the spring like a tension shackle can. A heavy-duty shackle must also be used in extreme applications, since the rear spring eye can be a contact point for rocks and obstacles in extreme terrain.
2. Removing the factory tension shackle isn't too difficult, unless the fuel tank on certain model vehicles needs to be dropped and the rivets chiseled or torched off the frame. The advantages of a tension shackle is that when the shackle drops horizontally it gives extra droop and travel to the suspension. A drawback to tension shackles is that tall lifts require lots of spring arch, which limits the flex of the spring.
3. Tension shackles work well with a moderately lifted aftermarket springs; in a GM application this is usually 4 inches or less. With a moderate- or low-lift custom spring, a longer than stock shackle might be used even though it can lower the ride height. These old rubber bushing have had it. Use polyurethane bushings, preferably with a beefy steel inner sleeve for durability and to keep the bolts tight. Polyurethane bushings also let the springs and shackles rotate through their full range of motion easier without binding.
4. A shackle flip can be an economical way to lift a vehicle. The factory leaf packs can be retained, saving hundreds of dollars. Sometimes the factory spring also has a heavier rating, which is hard to duplicate in a lifted aftermarket spring. A 10- to 12-inch lift can be achieved by using ORD's HD shackle with a 6- to 8-inch-lift rear spring. The best way to complete the lift on the front of the vehicle is to use a aftermarket lift leaf spring.