Add A Leaf

What an add-a-leaf does

An add-a-leaf is one extra leaf inserted into the existing spring pack. It adds arch, which lifts the vehicle, and it adds spring rate, which stiffens the ride and raises load capacity. The lift figures quoted here, 1 to 3 inches depending on the application, assume a spring pack in reasonable shape. On a pack that has flattened from years of hauling, the same leaf may give more apparent lift because it also restores the height that sagged away.

Because it works by stiffening the pack, an add-a-leaf is well suited to trucks that carry weight, tow or run a heavy bumper and tire carrier. It is a poor choice when ride quality is the priority; a full replacement spring with more arch and a softer rate rides better at the same height. Many owners use an add-a-leaf as a budget lift or to level a truck that sits low in the rear.

Short or long, and where it goes

The listings describe leaves as short or long. A long add-a-leaf is close to the length of the main leaf and is usually installed as the second leaf, right under the main. A short leaf goes lower in the pack. Longer leaves spread the added rate over more of the spring and ride a little smoother; shorter leaves add more lift per inch of thickness but are harsher. Pro Comp quotes exact figures for its kits, for example a 49.75 inch flat length, 3 inch width, 0.325 inch thickness and 105 pounds per inch rate, which lets you compare with a competing leaf directly.

Front add-a-leafs exist for leaf sprung front axles such as 1970s Ford F-250s and are sold for use with a specific brand of lifted spring. Make sure a front leaf matches both the truck and the spring pack it is going into.

Fitment and included hardware

• Match the vehicle and the axle position. Kits list year ranges such as 1984 to 2001 Cherokee XJ or 1994 to 2002 Ram 2500 and 3500; a Ram 1500 leaf is a different part.
• Check what comes with it. Most kits include a longer center pin or tie bolts, since the stock pin will be too short once the pack grows. Bushings and shackles are not included.
• Check for stated kit compatibility. Some Skyjacker leaves are intended to work alongside a specific Skyjacker lift kit number.
• Expect to need longer U-bolts, since the pack is thicker, and possibly longer shocks and a brake line extension once ride height increases.

Installation notes

Support the frame on stands, let the axle hang on a jack, and remove the U-bolts. Clamp the spring pack with a C-clamp or two before pulling the center pin, because a released pack springs apart with real force. Add the new leaf in the position the instructions call for, install the longer center pin, and tighten before releasing the clamps. New U-bolts should be torqued in stages to the spring maker's figure, then rechecked after a few hundred miles as the leaves settle. Keep leaf clamps or add new ones so the leaves do not fan out sideways.

Lifting the rear changes pinion angle slightly and may call for a driveline check on vehicles that are sensitive to it. Shock length should match the new ride height, and after any rear lift it is worth confirming headlight aim and getting an alignment on vehicles with adjustable rear geometry. Have the work done or checked by someone experienced if you are not comfortable working under a sprung load.