Carli Suspension CS-FSHACKLE-11 Fabricated Leaf Spring Shackles

Upgrade the rear suspension in your Super Duty with the Carli Suspension Fabricated Leaf Spring Shackles CS-FSHACKLE-11. Some of the jarring ride characteristics of your Super Duty can be attributed to the factory-equipped vulcanized bushings in the leaf spring packs and shackles. The factory shackle in your truck is very strong but the design is certainly not conducive to a smooth and comfortable ride. This isn't a big surprise as your Super Duty is made to tow, not be a luxury vehicle. The Factory leaf springs have a high-spring-rate and short-travel, so the OEM didn't need to design a shackle that rides well and is capable of extended suspension travel. The factory installed vulcanized bushings are a press-fit bushing that is often utilized by many OEMs. This bushing material is adhered on both points of contact.

In this case the vulcanized black bushing material (installed into the factory shackle) is adhered to both the shackle itself and the crush sleeve that the bolt goes through. The crush sleeve (silver sleeve that runs the length of the bushing) is very thick, which makes the actual bushing very thin. When your bushing is designed to only move as much as it can deflect and the deflection is minimal, your ride is going to suffer.

At Carli, they do everything they can to milk these trucks for the best ride quality possible. When looking at factory parts, those vulcanized bushings won't seem like a big deal. That's until you realize there are 6 total bushings, each of them fighting suspension movement in the factory configuration - the front leaf spring pivot, rear leaf spring pivot, and also the shackle pivot.

The Carli bushings are serviceable. Droop the rear end and grease them through the protected zerk fitting. You'll notice that there are channels for the grease from the zerk. The grease travels through these channels, around the crush sleeve and to the bushing face for optimal grease distribution and bushing life. In contrast to the factory bushing, the Carli Bushing assembly utilizes more bushing material and a thinner sleeve to prioritize ride damping.

You can also future proof yourself with these shackles. If you did ever manager to wear out the Carli Shackle Bushings, you just swap in new ones, reusing the crush sleeve. The factory shackles require replacement in their entirety when those bushings crack or rot out. In short, the factory shackle is a durable piece, but the press-fit vulcanized bushings bind and resist movement. This makes for a mediocre ride, no serviceability, and no ability to rebuild. The Carli Shackles won't break the bank compared to other mods and free up the rear end of your suspension while giving you a serviceable and rebuildable suspension component.