Everyone has heard of add a leafs and most of the time they are dismissed as being a stop gap for real suspension mods. While some of what you have heard may be true there are some benefits that you may not even realize.
First you must understand just what part of the springs are actually supporting your rig. For the most part your rig is only attached and supported by the top two leaves of the spring pack in the front (sometimes three in the back). All the other leaves are for the most part overload support. They only add stiffness to the main leaves. That first pic is a stock shackle and set of springs from the front of a 60.
Why do I say this? Take a look at the spring pack under your rig. The only leaves that span the full length from pivot to shackle are the top two or three. The others all taper down to the shortest one which is barely longer than the spring perch and mount surface on the axle.
Now imagine what would happen if any one of those bottom leaves broke or was removed. All your rig will do is settle down a bit or just lose some load carrying capacity. But imagine what would happen if it was one of the upper leaves that suffered some sort of failure? Depending on where it breaks the axle may move backwards, there will no longer be a solid connection to the frame and no longer any ability to carry weight in the rig. I got to experience the later on a trail run recently. No, not on my rig but I got to make the repair on another wagon to get the rig off the trail.
So what does this have to do with add a leafs? Full length add a leafs not only provide additional lift and weight carrying capacity they also provide extra support in case one of the main leaves breaks. Instead of the two or three full length leaves in the spring pack, you now have three or four. The add a leaf is not attached to either end but it does span all the way from the shackle to the spring pin. Gravity makes sure it is supporting the rig. The second pic is an add a leaf in an OME spring pack on the front of my BJ60. And after you take a good look at both these pics just what would you prefer to be under your rig.
While your intention may have been to gain a little ride height and some additional weight carrying capacity (if you run heavy like I do), the biggest benefit just may be the fact that with a full length add a leaf you are less likely to suffer a complete failure of the suspension that leaves your rig stranded in the woods.
