Need help deciding on leaf springs!

[MJ'sBlkBII]

I am going nuts trying to figure which leafs to put under the BII. I want to get rid of the sag and maybe gain 1-1.5". I am going to buy new so there is the 1st issue: BII or Explorer? How long will new BII springs be enough to bring the back end up? There is part # 42-821 with 5 leaves a 1020 lb cap. and 42-821XL with 6 leaves and 1500 lb cap. I like the idea of higher capacity but do I want the ride to stiffen as much as that might require?!
Moving to the other option then. Which Explorer spings to get instead? 43-967 with 1250lb cap. (sounds decent but has less arch than the BII springs so wouldn't it still sit lower?), 43-967XL with 1700 lb cap. (again to stiff?), 43-1183 which is a 3" wide tapper but it's leaf count seems backwards and the stack is over 2". Then 43-1159 to throw in too. According to SDT truck spring, 43-967 is for sprung over axles while 43-1159 is for sprung under axles. With a 6 1/2" arch on the sprung under, it is almost the same as the arch for the BII springs, would there be any difference in lift between the 2? How does arch effect ride height?
If someone could shed some light on this I would appreciate it. Feel free to use small words and speak slowly. LOL I have done some searching and I know I won't get a great deal of lift just from springs but I am trying to get better than what I already have and go from there.
Thanks y'all

 

[bilzy7]

Explorer springs have less arch cause they are meant to mount under axle on an explorer. I'm not sure how bronco springs mount. Longer shackles too might be an idea. Id assume you want a soft ride, but ability to not sag with some stuff in back. It's not like your gonna be putting a truck inside that thing so go with one of the middle choices.

 

[MJ'sBlkBII]

The Bronco is sprung over. I guess I'm confused over the arch numbers. To my way of thinking, if it has a higher arch number than it has more arch, therefore it equates to more lift since the center point is that much lower in comparison to ends. wouldn't a sprung under need more arch to give proper ride height? Does the increased arch just give more deflexion, while a more shallow arch adds stiffness and less flex, while still giving the same ride height?

 

[MJ'sBlkBII]

Ooohhh! Free arch is not a set measure across the board for ride height! Spring rates determine how much arch you need to achive said certain ride height! If you have a higher load rating, hence a stiffer spring, you don't need as much arch to get the same lift as you would from a softer spring due to reduced deflexion. Someone tell me if I finally a clue!
I'm still confused on the spring over/under bit though. I have found both 43-1159 and 43-967 called stock replacement for all years and models of explorers. Maybe one is for the Sport and the other for the 4 door? They do have different part numbers. Only explanation I have for the difference in specs. Possably one is later model years as they got heavier, but still will work for the older. I dunno. Gonna go for the 43-967 since it has the higher load rating. May make a basterd pack with my old springs to give a bit more lift and load cap. if I need it.
Sounds like plan.

 

[bilzy7]

Explorer sport uses 1 spring, or at least all I've seen have only had one. From my understand they are weaker metal(forget name of metal), it's alot light in rear. My explorer is 4 leaves and 1 overload leaf. It rides good, for a bronco 2, id say a sport model explorer spring would be softest ride.

 

[bilzy7]

Also each spring is rated at a different weight. So say top(longest) spring is the weakest, so then it hits other springs which are progressively stronger. Altogether giving it a nice soft bounce, or a hard hit.

 

[MJ'sBlkBII]

I got all that. I never had cause to put the spring rates/arch equation together. All of my other suspension building, and there isn't much at that, was with coil overs. I've been researchig this for a week and I came aross 1 sentence somewhere that put it all together just after I made the posting.
I ordered the 43-967 since it has the little increase in load cap. and seemed to have more info suggesting them to be the stock replacement. Shall see what happens.