4 link vs leaf spring Dual purpose (1 Viewer)
- Thread starter Ryan Davis
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ntsqd
technerd
Links are cool and all of that, but I would stay away for your uses. Coil springs aren't great for varying loadings w/o affecting the ride height. Go with the GM 63' leafs. I did that on my old Xcab and it not only rode nice unloaded, it didn't sag much when loaded for a week's worth of off-pavement touring & camping.
- Thread starter
- #3
The 63" springs are my plan for the rear. I was trying to figure out the best bet for a front sas set up. I can't find anything online about people using the 63" Chevy spring up front.
ntsqd
technerd
AH!! I thought you were talking about the rear, missed that somehow.
Was it me, and I've pondered this on two different trucks and the third truck has a set waiting on mounts, I'd go with a 2.5" c/o up front. They're more spendy than a 2" c/o, but you move more oil with every suspension movement so their damping will be better w/o having to be harsh. Slow speed you won't know any difference, but you will when sailing down a road in the Owyhee's or taking the back way into Paulina. (I grew up in Powell Butte)
I do not see a huge advantage in a 3 or 4 link over radius arms assuming that those arms are the right length. Usually if their length results in little to no front drive-shaft plunge then that's about right. 3-4 links are what all of the cool guys run and on paper they look better, but I just don't see the added effort paying off in the real world. I'm better sure that I am nearly alone on this.
Was it me, and I've pondered this on two different trucks and the third truck has a set waiting on mounts, I'd go with a 2.5" c/o up front. They're more spendy than a 2" c/o, but you move more oil with every suspension movement so their damping will be better w/o having to be harsh. Slow speed you won't know any difference, but you will when sailing down a road in the Owyhee's or taking the back way into Paulina. (I grew up in Powell Butte)
I do not see a huge advantage in a 3 or 4 link over radius arms assuming that those arms are the right length. Usually if their length results in little to no front drive-shaft plunge then that's about right. 3-4 links are what all of the cool guys run and on paper they look better, but I just don't see the added effort paying off in the real world. I'm better sure that I am nearly alone on this.
- Thread starter
- #5
My bad, I should have been more clear I was talking about sas swap out front. My lift keeps cracking at the steering knuckles and I'm not confident towing down the highway with the repairs.
In talking to a buddy of mine he's saying to use the coil over set up from a jeep. He said fab up all the mounts and just use the old jeep parts. What's your opinion on that concept?
In talking to a buddy of mine he's saying to use the coil over set up from a jeep. He said fab up all the mounts and just use the old jeep parts. What's your opinion on that concept?
Tigerstripe40
SILVER Star
I did a bunch of research on this very topic in regards to my Land Cruiser about 10 years ago. Here's the quick and dirty summary:
There's a lot of engineering that will need to go into a 3 or 4 link suspension system in order to make it ride well and drive correctly. It's not just bolting up the link parts and going. Fitting up used Jeep parts likely won't work well because a Jeep has a different wheel base and center of gravity when compared to your Toyota. Those are some of the most important aspect of designing a linked suspension.
I'd suggest that you find some books on setting up linked suspension, so you get a good idea of what concepts like antisquat mean, what they do, and how they affect your ride. After you've done that, look up the 4link calculator (or 3 link calculator) where you will put in wheel base, tire size, center of gravity, etc.
Heres a few from a quick google search:
Chassis Engineering by Herb Adams
Fundamentals of Vehicle Dynamics by Thomas D. Gillespie
Race Car Vehicle Dynamics by Milliken and Milliken
Once you've got a good plan there, then go start taking measurements from your truck. You'll find that the idea place to put your upper link mounts won't work because that's where the crankshaft of your motor is. So make some more drawing, then go adjust the 4 link calculator output so that you can make thing work in the real world, and then you need to decide the compromises that you will need to take on order to make it all work.
Oh and per my Land Cruiser? I just did a standard spring over with leaf springs.
2ndGenToyotaFan
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3/4 link is probably going to ride a little nicer, but the job as stated above will be more complicated.
Leafs are a more straight forward swap, done a million times by now...
Both can be made pretty bullet proof. I'd say it depends on your fabrication skills.
Leafs are a more straight forward swap, done a million times by now...
Both can be made pretty bullet proof. I'd say it depends on your fabrication skills.
- Thread starter
- #8
I'm told if I do the leaf I might not like how it goes down the highway. Is it a rough ride?
ntsqd
technerd
One of the trucks that I pondered radius arms for was my old '84 Xcab. I used OME front springs and the 63's on the rear. With 255/70 Bilsteins up front and 275/78 Bilsteins on the rear it rode exceptionally well for a leaf sprung truck. I saw going to coils up front as the next step better ride, but once I had the leaves dialed in I never felt like they rode badly. On your truck the key will be to put the spring mounts as high as you can, and then you'll have to sort out the steering because the off the shelf parts won't work on a truck that sits that low. I recently posted pics of the steering arm that I had to build, and it still managed to get into the 22R's oil pan a little bit.
I agree with the above, using Jeep parts might look like the easy way out but what it really does is tie you to using Jeep specific aftermarket springs. If the ideal spring rate isn't offered you'll be stuck. If you use the more expensive, but much more universal coil-overs then you can buy springs with rate increments of 50 to 100 in-lbs where you'll be lucky to even know what some of the Jeep spring rates are.
I agree with the above, using Jeep parts might look like the easy way out but what it really does is tie you to using Jeep specific aftermarket springs. If the ideal spring rate isn't offered you'll be stuck. If you use the more expensive, but much more universal coil-overs then you can buy springs with rate increments of 50 to 100 in-lbs where you'll be lucky to even know what some of the Jeep spring rates are.
- Thread starter
- #10
So if I decide to go leaf. Why wouldn't I be able to use a set of rear leafs from a late 80s Toyota? Or fronts from an early 80s Toyota?
Tigerstripe40
SILVER Star
You can use leaf springs from a 2017 F350 if you want to. Really, you can use any leaf springs that you want to fab the spring and shackle hangers in for. There are kits where you use Toyota stock leaf springs in a SAS, from the usual vendors (marlin crawler, trail gear, inchworm, all pro, ruffstuff, etc). Lots of this stuff is out there for your truck.
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- #12
I think F350 springs would be a little stiff haha. Still looking for something with flex so it doesn't break your back on bumps.
2ndGenToyotaFan
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"Rears up front" is a common swap for the old trucks. Any spring is going to involve custom mounts, and don't forget to address the steering situation before you start chopping. You're probably going to want to to with a "High Steer" setup from an aftermarket supplier.
ntsqd
technerd
My experience has been that the aftermarket high-steer stuff results in oil pan to drag-link clearance problems if you don't want a tall truck. It all works if you stay within their formula, but the bump-stops get spaced down off the frame and the ride height has to go taller than I want if there is going to be decent wheel travel.
With my '88 4rnnr there is no way in hell that I would ditch the IFS for leaf springs. I would go with radius arms and coil-overs or leave it alone.
With my '88 4rnnr there is no way in hell that I would ditch the IFS for leaf springs. I would go with radius arms and coil-overs or leave it alone.
- Thread starter
- #15
I run 5.29 gears, 36" and 37" tires and my steering knuckles keep cracking at the welds. It's not safe to have this problem running down the road towing a trailer with water.
Tigerstripe40
SILVER Star
The suggestion of F350 springs was intended as a joke, but also illustrates my position that you can use any leaf spring you want. It's all going to require some sort of fabrication. However, the 'usual suspects' make kits that includes spring hangers, jigs, shackles, (even springs).
All Pro: Solid Axle Swap Kit (SAS) | All-Pro Off Road
Trail-Gear: IFS Eliminator Kit 3
FrontRange Offroad: Solid Axle Swap Kit
Most of these are complete kits and include lifted leaf springs, steering, shocks, brake rotors. You just need to supply the axle (though you can get a complete axle through Trail Gear as well, though personally if I were to get a custom front end, I'd want a 609 style and just ignore the toyota parts).
You can also order these kits without the leaf springs, and have some springs custom made for your application by companies like Deaver, Triple A spring, Alcan, and likely many many others.
You could also take stock rear pickup leaf springs and mix and match leaves until you get the ride you want. OR you can use soft springs and install airbags in order to adjust the ride as you see fit.
Tigerstripe40
SILVER Star
If you want to retain IFS for ride quality and upgrade the strength of the knuckles and stuff, theres Solo Motorsports XLT suspension system
XLT Series Pickup / 4Runner 86-95.5 Xtreme Long-Travel Front Suspension Kit - Solo Motorsports
ntsqd
technerd
Why are the knuckles welded in the first place? Find some new ones that aren't welded at all.
This. Something is not right with that housing. Got any photos?
If the type of off-roading you're doing with 37s on IFS has not translated into lots of broken parts then you don't need to spend the time/money engineering links (whether it be jeep stuff or not). You don't need them. Especially if this will spend the majority of its time on the streets towing... just doesn't make sense. Do what everyone else does and use leaf springs. It works. Plain and simple. You have some reading to do it sounds like. Use whatever springs you want to - lots of options. Obviously you'll have to take care of the steering setup and the myriad other things that come along with a SAS.
