leaf spring question
Allright - bit of an odd question that probably can't be perfectly answered given all the variables, but going with approximate gut feeling from those of you with experience in leaf springs on old vehicles (especially CJs or YJs):
How much will the free arch of the spring reduce when under weight of the vehicle as compared to when its just lying on the floor or off the shelf. Obviously the spring stiffness matters the most, but these old jeeps have stiff springs (no flexy softride springs - too narrow and to far inboard for stability). In this case its a pair of superlift (probably pretty stiff) front leafs under an old CJ5 with 6.5" of free arch. Thinking 2-2.5" inches of free arch would be lost when under the weight of the vehicle? more..less?
Also, as the free arch is reduced and the leaf is flattened by the vehicles weight, the straight line eye to eye length (sometimes called the datum line) will increase. Any guess by how much?
My current front leaf springs are too short (or too stiff) as the front shackle sits vertically instead of having a forward angle (in dangers inverting shackle as well as limits droop). Found a pair of supposedly never used superlift 4" lift springs (specifically for early cj) for the front and trying to see if they will work. They are 38" straight line eye to eye just sitting on the floor, which is just less than my distance between spring hangers (38.5"). Under vehicle weight I would like something that flattens to about 4-4.5 inches of arch and lengthens to 40-41" straight line eye to eye.
Sorry I have no info on the true spring length (along the length of the top leaf) but doesn't really change the question even if I did.
1958 Willys Wagon
2010 Tacoma TRD