Leaf springs: miltiple thin or a few thick?

COChev

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why is it better to have multiple thin leaves as apposed to 4-5 thicker ones? in the end you need "X" amount of arch and spring rate to ride at a given hight. you pre runner guys are saying that more arch is better but doesn't this eventuall equate to a stiffer ride? is the arch only for good droop? cause you can have all kinds of arch but if the springs are soft it will have a lower ride hight then a stiffer set. so getting back to the number of leaves- if you had a 4-5 leave pack with as much arch as say a 10 leaf pack and they both had the same overall spring rate, woud there be adiffernce in ride? come drop some leaf spring knowledge on me!
 

drtdevil93

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it comes down to this: try to bend a 1/2" thick leaf. its hard. it barely wants to bend. now you put it with 4-5 others that are even shorter, meaning much stiffer. and the bottom leafs of the spring hardly come in to play. it puts all of the strain on the first 1-2 leafs.

with a 10 leaf pack: try to bend a leaf that is 1/5" thick. its real soft. it will move very easily. now put it with 9 other shorter leafs. it doesnt mind moving. and those bottom leafs actually come into play. they carry a lot of the load. it becomes progressive. another advantage is that instead of having leafs with as much as 8" between leafs (graduation), our way puts around 3 inches, meaning less chance of breakage, bending, and sagging.

its a subject that is easy to understand, but hard to REALLY understand completely, if that makes any sense.

another advantage of a spring with arch is this: as it moves up, it also grows horizontally on the rear of the spring, much more than a flat spring does. this is why prerunners have long shackles on them. the advantage of this is that much of the impact is transferred back through the shackle. this is the main reason why our tacoma spring is such a big improvement over stock. the stock spring doesnt move the shackle more than about an inch through the full cycle (since its flat). ours moves it around 3 inches, and it makes a huge difference in ride, and spring life as well. we repair a good 2-3 stock tacoma springs every week (broken clip leaf).

the things that make a difference are these:
-shackle movement
-ability of spring to move
-good spring rate
-proper graduation

im sure i missed a bunch of stuff, so keep up with the questions.

erik
 

COChev

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thanks, much clearer now. so the thickness of the leaf gives it is spring rate more so than the arch it has built into it. more arch is more travel. more leaves is more progression in the spring rate. sound right? does there come a point where too much arch in a thin leaf will make it stiffer than thicker one with less arch? there has to be a stopping point. also too thin a leaf with lots of arch that gets worked hard will fail before a thicker one. i'm sure you have these details already dialed but it has to vary from truck to truck due to weight difference, use, etc.

i think this would also work well in the word of trail running and rock crawling. a spring that has good flex (articulation) and a nice progressive ride to boot.

good info here! thanks,

jason
 

rdc

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hey dirt devil 93. how much does deaver charge for a race pack for a 97 tacoma??

Tha Realest
 

Donovan

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On a compression type shackle how does the shackle angle affect the spring rate or does it? What angle should the compression type shackle be, when it is at rest?

Donovan
 

COChev

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wouldn't you want to maybe figure it the other way? make the shakle straight up and down at full droop then make sure your shackle is long enough so that the rear spring eye doesn't hit the frame. maybe figure out your spring eye to eye at full arch and flat and use a tape measure to simulate your shackle. for example if your spring was 52 eye to eye at arch and say 58 flat. pull your 52 inches from the front eye to the frame (eithere through, above or below) make a mark. then put the the dumb end at that mark and move it in an arc back. pull another tape from the front eye and find where the first tape meats 58 inches on the other tape without hitting the frame. make any sense? this is how i was going to figure mine. i want to run the springs under the frame and pivot in the frame.
 

COChev

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i've seen other threads on here where guys mock everything up and just use the main leaf so they can jack up the rear axle until the spring is flat. still have to find a starting point for the shackle pivot though.
 
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