Longer Leaf Spring Shackles

Shackles are a vital part of a leaf sprung suspension. Flexing of the elliptically-shaped leaves changes the straight line distance between the spring pack's mounting eyes. A shackle is placed at one end of the spring pack to allow for this change in length.

Wheel travel and ride height can be increased, within reason, by increasing the length of your suspension's shackles. This is a relatively simple and cost effective way to fine tune your ride's ride. Furthermore, a shackle lift will not increase axle wrap like the other budget lift option, a block.

Pinion angle and the swinging arc of your suspension should be kept in mind if a shackle lift is considered. Changing the length of the shackles will affect the angle of the pinion on that axle. This can be good or bad depending on the application. Also, the path that the wheel follows when the suspension cycles, the swing arc will be changed. Research and careful analysis of your setup should help you determine if a shackle lift is right for you.

We recently found a shackle to increase the ride height of the rear of our heavy duty dodge diesel made by Truckin' Suspension Lifts. The shackle option was a good choice for our application since it would not affect the spring rate or increase axle wrap. The long wheelbase and small relative lift of 1.25 inches meant that we would not be drastically changing our pinion angle or suspension geometry.

	The Truckin' Suspension Lifts...        read full caption The Truckin' Suspension Lifts shackles have a few nice features. There are two sets of holes giving you the option of a 2.25-inch or 3.25-inch increase in shackle length. It should be kept in mind that the actual vehicle lift will be about half of the increase in shackle length. To deal with the added stress, the shackles are made out of metal that is about 50-percent thicker than the stock versions and have greasable bushings.	While searching for shackles...        read full caption While searching for shackles we learned that Dodge has used a few suspension configurations on this body style truck. Luckily, ours is a compression shackle version that enables the use of a longer shackle to achieve a moderate lift. It should be noted that changing to a shorter-than-stock shackle is not an option since it would not allow for adequate spring movement and could bind.If we had a tension shackle (where the shackle hangs above the frame mount) setup, we could still add a longer shackle for a little extra travel, but we'd actually be losing ride height.
Installing the longer shackles...        read full caption Installing the longer shackles was relatively simple and completed in an afternoon in our garage. We placed jack stands under the rear frame of the truck, removed the wheels and let the axle droop until the weight was removed from the shackles. Then we removed the mounting bolts and lowered the axle further until there was room for the longer shackles. Finally, we used the original bolts to secure the shackles and reinstalled the wheels.	Gauging the lift achieved...        read full caption Gauging the lift achieved can be done by measuring the gap between the top of your tire and the bottom of the wheel well. This picture shows the after measurement at about 10 inches. Before the install the gap measured at 8.75 inches, meaning we gained 1.25 inches of lift. This was just what we were looking for to level out our truck's stance.	Earlier we mentioned how longer...        read full caption Earlier we mentioned how longer shackles will change the pinion angle on the axle. It is important that the angle between the pinion flange and the driveshaft be within a certain limit. A high angle between the pinion and driveshaft can cause the U-joints to wear rapidly and fail. Ours appears to still be in good alignment after the shackle swap. One thing we did note though, is that we gained more inches in travel than we did in lift, so now the shocks on this truck are overextending at full droop and we'll have to address that.