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Discussion Starter · #1 ·
So I finally decided to bite the bullet and ditch the leaf springs in the front. I think it’s worth getting the controversial matter out of the way first… YES, leaf springs are super cheap, simple, capable, and can flex very well. With the right shock valving, this Jeep rides over bumps in the road really smoothly as well. I assure you I have gotten as much as I can out of the leafs as I can over the last 5-10 different iterations and tweaks. I’ve tackled everything from spring rates, bushings, bolts, shackles, shackle angle, and even leaf spring length but I’m still left wanting more. At the end of the day, I’ve probably spent as much on leaf springs as I would’ve had I just gone to coilovers early on but I also know that’s not a totally fair comparison considering SUA, SOA, new front axle, bushing changes, XJ leafs, etc are significant steps in progression that many people stop at. I’d say it’s less about what the suspension can do and more about what how it does it. I’m going to put some pictures below showing how the leafs flex under heavy load with the rear coilovers on the bumps and then how they don’t flex until the coilovers are on bumps. The driveway shot is on a 16” wall and the drivers front suspension compressed a whopping 1/8” while the passenger rear shock compressed 5” and the drivers rear drooped 8”. If you’ve heard me talk about suspension imbalance, this is what I’m talking about.

I’m literally swapping out leaf springs with 14” of travel for coilovers with 14” of travel so I think the comparison will be really interesting to see.

A few shots of the Jeep pre-build...
 

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Discussion Starter · #2 ·
Still missing the link material but have pretty much everything else and will likely start tearing the Jeep apart this weekend.

So far I've spent the following:
$100 - 4 Square tube 2 x 2 x .25" for links shipped from Midwest Steel Supply
$580 - 2 Fox 14" Emulsion shocks 980-02-011 shipped from AJ USA
$180 - 4 Summit Racing Coilover springs (Actually only bought 2 and have some extras but counting the price as if I purchased all 4)
$550 - All the tabs, heims, and equipment shown below from Barnes4WD (Thanks to DirtLifestyle's youtube channel for the 10% off coupon)

So at this point I'm at $1410 spent. Still need limiting straps and may need a few more odds and ends so we'll see.

Edit: Added a 4ft x 1.5" x .120" wall tube for the shock tower cross brace ($15) and $30 for some limiting straps. I also figure I spent about $10 on grade 8 bolts to mount the shocks and 2 cans of bed liner paint ($15).

Grand total - $1480
 

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This is a really cool build. Your other thread made me dig back into some more reading on anti squat, anti dive, roll centers, etc. again. Very thought provoking. Will be following along for sure.
 
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You will not regret linking the front. I did the dual triangulated 4 link in the rear and thought that I would be happy maintaining leafs in the front. I wound up destroying a pair of leaf packs every trip I took. The big tires and low gearing was too much and I had horrible spring wrap. Once I linked the front I am finally 100% happy with my suspension, both front and rear.
 

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Discussion Starter · #5 ·
Well the easy part of getting the old axle out is done. I suspect most of the weekend will be spent cutting off old brackets and prepping the frame/axle.

On a side note, I loaded up the Jeep with everything I normally take on the trail minus a small cooler. That's all tools, hi-lift jack, full tank of fuel, and my butt in the seat. Parked on the scales as evenly as I could and was surprised by how evenly weighted the tires were....along with how much it weighed. I guess if I had taken 210lb self, tools, jack, and had 10 or more gallon less fuel, the weight would probably be more what I was expecting.

Last picture is the current plan for the 4 link.
 

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Leaves at each corner, set up as best you can.


What does or doesn't it do that makes you desire changing to links and C/O`s ?


I get the mismatch side of things. Let`s take that away from the equation and discuss a good properly set up leave suspension.


Not a much of a suspension guy, more of a powertrain and steering type person. I see all these fancy link setups with high end dampeners and think that this is a suspension more suited to faster speeds than the leaves.


Like you I`ve strived to optimize the leaves with quality springs, good damper valving and correct geometry. Road manners are supple and the trail habits for the speeds we normally run are good. Its only when the speeds are upped do I wish for a better suspension. Primarily in the rear where it becomes tail light. Since my off roading leans towards the technical slow speed stuff I`ve not felt a need to change anything.


What am I missing here ? I just don't know suspension well enough to be able to make an accurate judgment.
 

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Discussion Starter · #7 ·
@jsawduste I've been trying to figure out a way to justify it in words without being super controversial and honestly I'm struggling. So I'll take my personal experience and combine it with some cost comparison.

From my experience, coils do a much better job at fully articulating the suspension while minimizing body roll but it's a bit of an apples to oranges comparison because the price of normal leaf spring suspensions is not on the same playing field as normal coil suspensions. I imagine that a well made set of leaf springs with lots of thin leafs in the pack can do a similar job but realistically the cost of those leafs springs begins to rival the cost of coilovers and a link setup. So with that said, I found a set of 4.5" leaf springs from Deaver with a 9 leaf pack for $860 which is $1720 for a full set of 4 leaf springs. Combine that with some high quality, properly valved shocks and you're easily up over $2000 and probably over $2400 if you want a nice tunable shock instead of a shock that most agree is pretty good. With leaf springs, you still have to worry about over flexing the leafs or bending the leafs and destroying them, bashing it on rocks, and the constant bushing replacement. IMO, that's too many negatives without a whole lot of customer backing to really prove that the investment is worth it. You can still break stuff with coilovers but you're generally not wearing them out under normal usage and if you do break something, it's usually a single link, heim, or frame bracket which are often cheap to replace or even carry a spare for.
 

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Being out of my comfort zone I went with the Deaver route.


They wanted plenty of info to make up a custom pack. In the end we ended up switch a couple main leaves for thicker (stiffer) leaves.








Spring weight and vehicle weights/suspension travel in hand one of the U4 shock tuners set up the remote resi`s. At least as best he could without an actual shock testing session.




Added to the mix was roll calculations and a custom stabilizer bar made up that worked with the Anti Rock arms.


At this point it worked pretty well. Not the cheapest but functional for my needs.
Still wonder about the advantages that a well setup link C/O might give. However at this piint its probably money best spent enjoying the rig as is.
Be watching your progress and look forwards to the evolution.
 

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Discussion Starter · #9 ·
Being out of my comfort zone I went with the Deaver route.

They wanted plenty of info to make up a custom pack. In the end we ended up switch a couple main leaves for thicker (stiffer) leaves.

Spring weight and vehicle weights/suspension travel in hand one of the U4 shock tuners set up the remote resi`s. At least as best he could without an actual shock testing session.

Added to the mix was roll calculations and a custom stabilizer bar made up that worked with the Anti Rock arms.

At this point it worked pretty well. Not the cheapest but functional for my needs.
Still wonder about the advantages that a well setup link C/O might give. However at this piint its probably money best spent enjoying the rig as is.
Be watching your progress and look forwards to the evolution.
Well based on your scenario, I'd say you're likely getting more out of your leaf springs than at least 99% of leaf spring users. I'd also venture to say that you're getting more out of your leaf springs than the majority of people running coilovers who didn't use or don't understand how the 4 link calculator works and/or don't understand how to tune their springs/shocks. The other thing that's worth mentioning is the simplicity of leaf springs vs the complexity of a link suspension. I've got a friend who sat his Jeep down at the end of 2018 to do a 3 link front and 4 link rear. 2 years later and it's still down. He's a very capable fabricator but I think analysis paralysis got the best of him and there are too many compromises that he just hasn't been able to work through efficiently.
 

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Discussion Starter · #10 ·
Got the axle and frame stripped. The dog has been hanging out as long as I'm not making a ton of noise. Moved the axle back under the Jeep and set it at ride height so I can start working out the best design. Unfortunately, an inch or two here and an inch or two there and my numbers are getting a little worse. I'm pretty confident a sway bar is going to be in my future for on road riding. I also tacked up a couple dummy links using some thin wall square tube I had laying around from another project. That way I can check clearances.

The upper link truss on the axle was there when I bought it so that kind of sets the height of the upper links.
 

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Just curious. What are the anti dive numbers on this setup?
 

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Discussion Starter · #12 ·
Anti-dive is 107. The calculator is meant for a rear suspension so a lot of things are reversed. My understanding is that 107 anti-dive raises the front slightly under braking but is basically a 93 in anti-squat when under acceleration in 4wd. The other thing that I think people forget is that the loads on the links will be reversed so compression is on the upper links and tension on the lowers. Therefore, you may not want to go too skimpy on the upper links in the front or they might buckle.

One thing I'm not sure of is the roll axis and it's tendency to oversteer/understeer. I would think that oversteer in the rear would lead to understeer in the front but I can't seem to confirm that. Regardless adjusting the upper links which have some wiggle room barely affects the roll axis at all. Meanwhile, the lower links are maxed inboard on the frame and outboard on the axle which help the roll axis the most. I can lower the roll axis by raising the lower links on the axle which raises the loads too much or lowering the frame mounts for the lower links. I'm already planning to put 1.25" spacers below the level of the frame so any more is really going to be awkward and probably create an anchor offroad.
 

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Discussion Starter · #14 ·
I would build it at bump and not ride height. Things get tight quick. 1/2" difference in link location could be the difference in 3" in up travel.
Well I'm getting the setup at ride height to work out the numbers. Once I get the setup decided, I will verify that bump isn't a problem or will set my bumps accordingly. Everything that can change is just being tacked in place right now. I think my biggest problem will be the upper link mounts on the axle. They've got about 4-5" before contacting the radiator or engine pulley which is all the up travel I was expecting but that will definitely be a hard stop and I'll want plenty of clearance to ensure they can't hit.
 

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Discussion Starter · #16 ·
Tuck them in right behind the radiator on either side of the crank pulley and just missing the lower radiator hose.
Yeah that's kind of the plan but it'll be tight. I'm also considering cutting the top of the upper link mounts off as well to give a little more clearance. I'll get some pictures later.
 

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Well based on your scenario, I'd say you're likely getting more out of your leaf springs than at least 99% of leaf spring users. I'd also venture to say that you're getting more out of your leaf springs than the majority of people running coilovers who didn't use or don't understand how the 4 link calculator works and/or don't understand how to tune their springs/shocks. The other thing that's worth mentioning is the simplicity of leaf springs vs the complexity of a link suspension. I've got a friend who sat his Jeep down at the end of 2018 to do a 3 link front and 4 link rear. 2 years later and it's still down. He's a very capable fabricator but I think analysis paralysis got the best of him and there are too many compromises that he just hasn't been able to work through efficiently.
Thanks for your input. Been off the gird for a few days on a wheeling trip.

Several; new builds joined this time. All with link suspension and no two the same design/setup. It was very interesting watching how the vehicles reacted to various obstacles. And than how the owners reacted to the performance.

One of the guys set up a short but varied obstacle course of sorts. We ran through it while he did video.

By far the worst was a JK running an EVO coilover kit with Kings. Typical SD/14 bolt on 40`s with a stock WB. The vehicle simply didn't react very well. The squat was way off and the ultra wide mounting of the front links to the axle created a lot of apparent binding. The F/R balance was way off for the tire size and WB.

An LJ with a RK system......at least it had an RK sticker........looked pretty good but a sheared rear track bar mount ended that guy early. He didn't want to get it welded up...He left early...... ??

Waternut, as archaic as the leave system is. In the group we ran this weekend it simply worked better on the whoops and ledges, rocks etc. Flex wasn't an issue. No unexpected unloading or wheel hop in the sand. The setup simply cycled up and down in a controllable manner and kept the Jeep planted.

I'm very envious of the undertaking your doing. From reading here and several other sites your a member of you have a good grasp of the dynamics and will be able to make the system work well. Not many can say that. It really makes sense when you consider the cost of custom leaves and shock tuning.

Was lucky that the folks at Deaver had done the homework and was able to supply a package that worked pretty well straight away. Watching the video`s was reveling.
 

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Discussion Starter · #18 ·
Thanks for your input. Been off the gird for a few days on a wheeling trip.

Several; new builds joined this time. All with link suspension and no two the same design/setup. It was very interesting watching how the vehicles reacted to various obstacles. And than how the owners reacted to the performance.

One of the guys set up a short but varied obstacle course of sorts. We ran through it while he did video.

By far the worst was a JK running an EVO coilover kit with Kings. Typical SD/14 bolt on 40`s with a stock WB. The vehicle simply didn't react very well. The squat was way off and the ultra wide mounting of the front links to the axle created a lot of apparent binding. The F/R balance was way off for the tire size and WB.

An LJ with a RK system......at least it had an RK sticker........looked pretty good but a sheared rear track bar mount ended that guy early. He didn't want to get it welded up...He left early...... ??

Waternut, as archaic as the leave system is. In the group we ran this weekend it simply worked better on the whoops and ledges, rocks etc. Flex wasn't an issue. No unexpected unloading or wheel hop in the sand. The setup simply cycled up and down in a controllable manner and kept the Jeep planted.

I'm very envious of the undertaking your doing. From reading here and several other sites your a member of you have a good grasp of the dynamics and will be able to make the system work well. Not many can say that. It really makes sense when you consider the cost of custom leaves and shock tuning.

Was lucky that the folks at Deaver had done the homework and was able to supply a package that worked pretty well straight away. Watching the video`s was reveling.
A lot of good insight right there... I had 2 friends come over today who are looking at linking their rigs and wanted to get an idea of what was involved. I'll be impressed if either of them open the calculator and even more impressed if either actually asks a question on what something means.
 

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Discussion Starter · #19 ·
Well I think I'm done until Thursday or Friday when I get the link material in. I'm not seeing any problems with clearance but tough to cycle the axle when I only have 1 upper and 1 lower link (all the spare material I had). The rear mounts for the upper and lower links look close but it will take about 8" of up travel for the lower link to the hit mount for the upper and I'm only planning for 4-5" of up travel.

It's kind of funny that I've extended some mounts and cut others down. I may still cut the upper link mounts down on the axle if I need more clearance but we'll see. Everything is still just tacked in place if there is some kind of clearance issue.
 

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Since you have a couple of days.
How did you choose the coilovers?
How about the valving? From what I’ve found 50/70 is what the standard is for those parts.
Believe these are the same on the back, felt any need for different valving? Being emulsion shocks, ever feel any fade? I know you’re not desert racing but trail riding can work the shock fairly well.
 
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