Radius Arm Suspension

[Beams37]

Hey Guys,

I've done a little searching and reading the inter-webs. I have a couple of questions about radius arm suspension and few other items.

If Toyota saw the benefits of moving to a radius arm suspension in the 80 series, how come no one has created a kit for the 60? I also notice that most guys do not even consider this as an option.

My other question: Why is everyone against a multi-link set up? It seems like with a pan-hard bar, it would be fine for normal driving conditions. However, it seems like most guys will only do this on true "hardcore" rig.

For me, I want a good ride on road (which in Memphis is riddled with potholes) and still have solid performance off road. Seems like radius arm or multi-link with a pan-hard bar would do work.

Can someone help me out?

 

[3_puppies]

I'm thinking unless the rig is lifted, there isn't enough clearance or room for everything.
Also a bit of engineering and fabrication is needed.

 

[Beams37]

Agreed on the first point. But I would prefer to have a smoother ride when lifted. I have OME suspension lift, but would think that a radius arm set up or a multi-link set up would ride better.

As for the fab and engineering, that is what is worrying me. That is why I am surprised that no one has created a kit to convert from leafs to radius arm.

Wouldn't it make sense to build a lift and radius arm conversion kit?? Do any vendors offer one-off solutions??

 

[lcwizard]

Not enough 60's out there. You'll get more travel out of a leaf unless you use a missing link arm on one side. But then all the braking torque is then loaded to one arm so your bracketry should be robust. I wouldn't trust stock 80 radius arm mounts for that. I've seen 80's that they try to pull a consistent 10+ inches of travel rip the mounts of their housing. With radius arms as the wheel droops the caster rolls forward. as it compresses the caster rolls back. If the right side droops and the left side compresses the radius arms are trying to twist the axle tube right out of the diff.
Smaller Danas with pressed in tubes do it all the time. The Dana 35s in the unibody Cherokees is notorious.
A linked suspension avoids the limitations of the radius arm..
Most shops I've seen will charge 6~10,000 per end for a good 4-link set up with good coilovers

 

[lcwizard]

The cheapest route would be pull the parts from an 80 if you want radius arms.
Before you do all that, pull the bottom leaf from your front pack and test it.
Leaf springs can ride soft if that's how they're built. My 60 rode as well as an 80 with the OME coils
with the leaves I had built. Leaf springs cost a lot more than coils so the manufacturers are all going coil

 

[Beams37]

Not enough 60's out there. You'll get more travel out of a leaf unless you use a missing link arm on one side. But then all the braking torque is then loaded to one arm so your bracketry should be robust. I wouldn't trust stock 80 radius arm mounts for that. I've seen 80's that they try to pull a consistent 10+ inches of travel rip the mounts of their housing. With radius arms as the wheel droops the caster rolls forward. as it compresses the caster rolls back. If the right side droops and the left side compresses the radius arms are trying to twist the axle tube right out of the diff.
Smaller Danas with pressed in tubes do it all the time. The Dana 35s in the unibody Cherokees is notorious.
A linked suspension avoids the limitations of the radius arm..
Most shops I've seen will charge 6~10,000 per end for a good 4-link set up with good coilovers

So why did Toyota move to the radius arm on the 80 if there's so many issues? Is just that the 60 geometry isn't happy with radius arms? There has to be some kind of solution for this. Right?

On the positive side, I love you products. Keep up the great work!

 

[lcwizard]

The radius arm is very reliable, few moving parts. Ford has used it for about 60 years. Rover also uses it.
As long as you don't overdo the lifts and travel it's great. Most car manufacturers don't choose a design with
the intent that everyone will modify it. A four link is more advanced and tuneable but there'e more moving parts.
Toyota used it on the 80 rear. A linked front is more difficult because you have to clear engine, exhaust and steering. the radius arm
setup is nice and compact. It would be costly to make a kit. Slee sells just arms for around 1100.00. Shocks, brackets, panhard
and related would bring a well done kit into the 2000~2500 range. Add shop labor and i'd figure 4~5000.00

Here's a Ford kit

WFO DMAX/HD 6" SAS Kit using Ford Superduty Axle (Radius Arm) | Chevy GMC 2500/3500 HD 01-10 | WFOConcepts.com

 

[NCFJ]

You are not the first to want to do something like this. I am building a truck for a customer currently, putting a 87 FJ60 body on a 92 FJ80 roller and adding an LS3 drive train.

Warhorse-LS3 C&C & more

You have to make the wheelbase shorter

Then you have to modify the rear frame rails to accommodate the rearmost body mounts for the 60 body

I did it like this

Get all of the body mounts in place and welded in

 

[NearJetties]

There is also the harvest the 80 series suspension route

2017 Rig of the Year - FJ60Cam’s 1985 FJ60

 

[cruiser enthuiser]

The radius arm is very reliable, few moving parts. Ford has used it for about 60 years. Rover also uses it.
As long as you don't overdo the lifts and travel it's great. Most car manufacturers don't choose a design with
the intent that everyone will modify it. A four link is more advanced and tuneable but there'e more moving parts.
Toyota used it on the 80 rear. A linked front is more difficult because you have to clear engine, exhaust and steering. the radius arm
setup is nice and compact. It would be costly to make a kit. Slee sells just arms for around 1100.00. Shocks, brackets, panhard
and related would bring a well done kit into the 2000~2500 range. Add shop labor and i'd figure 4~5000.00

That money for a comprehensive kit doesn’t seem out of line to me. I mean the deluxe OME kits aren’t much less than that. If someone made a comprehensive kit for swapping 80 suspension and 80 axles onto a 60 chasis that offered around 2.5-3” of lift and handling characteristics similar to the 80 I’d be ALL OVER IT.

I don’t have the time or the ingenuity to tackle such a project ala #FJ60Cam style So a kit like this would be ideal for me and I’d be willing to pay for it. I suspect I’m not alone.

Mud Vendors are you listening...?

Cheers!
-Ed

 

[Beams37]

You are not the first to want to do something like this. I am building a truck for a customer currently, putting a 87 FJ60 body on a 92 FJ80 roller and adding an LS3 drive train.

Warhorse-LS3 C&C & more

You have to make the wheelbase shorter

Then you have to modify the rear frame rails to accommodate the rearmost body mounts for the 60 body

I did it like this

Get all of the body mounts in place and welded in

I've been following this build and I am very impressed.Maybe I'm crazy, but seems like this could be a very expensive venture. Right?

 

[Beams37]

The radius arm is very reliable, few moving parts. Ford has used it for about 60 years. Rover also uses it.
As long as you don't overdo the lifts and travel it's great. Most car manufacturers don't choose a design with
the intent that everyone will modify it. A four link is more advanced and tuneable but there'e more moving parts.
Toyota used it on the 80 rear. A linked front is more difficult because you have to clear engine, exhaust and steering. the radius arm
setup is nice and compact. It would be costly to make a kit. Slee sells just arms for around 1100.00. Shocks, brackets, panhard
and related would bring a well done kit into the 2000~2500 range. Add shop labor and i'd figure 4~5000.00

Here's a Ford kit

WFO DMAX/HD 6" SAS Kit using Ford Superduty Axle (Radius Arm) | Chevy GMC 2500/3500 HD 01-10 | WFOConcepts.com

I don't need the tunability or large amounts of travel. And, I do see how it could be complex on the front. With the LS swap, it is already tight up front. Now I see why some go with SOA from and Linked rear.

I guess if it was easy and cheap, more people would be doing it.

 

[Beams37]

There is also the harvest the 80 series suspension route

2017 Rig of the Year - FJ60Cam’s 1985 FJ60

SO ... Cam lives here and I completely forgot that he has the 80 suspension crammed under his truck. He and I may have to talk !!

 

[lcwizard]

That money for a comprehensive kit doesn’t seem out of line to me. I mean the deluxe OME kits aren’t much less than that. If someone made a comprehensive kit for swapping 80 suspension and 80 axles onto a 60 chasis that offered around 2.5-3” of lift and handling characteristics similar to the 80 I’d be ALL OVER IT.

I don’t have the time or the ingenuity to tackle such a project ala #FJ60Cam style So a kit like this would be ideal for me and I’d be willing to pay for it. I suspect I’m not alone.

Mud Vendors are you listening...?

Cheers!
-Ed

that wouldn't include the 80 axle. It's wider than the 60. You'd need that for for the clearance to stuff the coil between the frame and wheel.
Some shop will need to invest a few hundred hours and quite a bit of money in that project. If you're doing that why not do a rear kit. While you're there you might as well make the rear links longer. The stock links are barely long enough for a proper lift over 4".
That's why I developed the FRAB ( front radius arm bracket) that Manafre and others sell. 15 years ago I built a kit for 80 suspension that would let you go to 6" lift with stock geometry. I built 80 kits. 45 sold, mostly to Europe. US 80 owners didn't truly understand 4 link geometry
and didn't feel they needed it. The FRAB was part of the kit along with front and rear panhard drops and lower rear arm drops, front an rear adjustable panhards and upper rears that were adjustable on the truck without removing them. The FRAB is still around . Much of the rest hit
scrap bins.
Big projects seldom pay off in a small market.
Rod from Kaymar parked a motorhome here while he worked on the FJ Cruiser rear bumper. I let him use the shop and gave him a hand whenever
he needed it. By the time the first one hit Man-a-Fre , when all costs were tallied, tooling, time and shipping back and forth of the first couple prototypes to fit, he had nearly 50,000 in the project. Al sold less than ten the first year.

 

[MountNGoat]

There is also the harvest the 80 series suspension route

2017 Rig of the Year - FJ60Cam’s 1985 FJ60

I wheeled Hole In The Rock with @FJ60Cam and can attest to it's functionality. It gave me the inspiration for what I'm doing to my 60.

 

[MountNGoat]

On my 60 I'm trying out some of these concepts. In the rear I've swapped in a late 80 series rear axle along with SOA and 63" Chevy springs. A traction bar will be added to control axle wrap and a sway bar with quick disconnect links will be fitted. Up front I've gone with 80 series radius arms, King coilovers, a Front Range 80-width axle housing, and Front Range knuckles with keyed steering arms. I'll be running 37's. Total lift is about 6". To get, hopefully, a better ride quality I am inverting the radius arms, but this will also serve to provide better clearance under the axle housing. This will be going to Rubithon this year, and hopefully it is the good compromise between a trail rig and an overlanding rig that I'm hoping for. This work is being done by the good folks at Valley Hybrids. (and yes the exhaust is being rerouted ).

 

[cruisermatt]

On my 60 I'm trying out some of these concepts. In the rear I've swapped in a late 80 series rear axle along with SOA and 63" Chevy springs. A traction bar will be added to control axle wrap and a sway bar with quick disconnect links will be fitted. Up front I've gone with 80 series radius arms, King coilovers, a Front Range 80-width axle housing, and Front Range knuckles with keyed steering arms. I'll be running 37's. Total lift is about 6". To get, hopefully, a better ride quality I am inverting the radius arms, but this will also serve to provide better clearance under the axle housing. This will be going to Rubithon this year, and hopefully it is the good compromise between a trail rig and an overlanding rig that I'm hoping for. This work is being done by the good folks at Valley Hybrids. (and yes the exhaust is being rerouted ).

Neat... but you won’t need the traction bar with the 63’s if you’re using the right 3/4 ton springs. Extra weight.

You should start with a sway bar in the front first instead of the rear. Why do you need quick connect fittings?

What shocks and valving are you starting with for the rear?

A lot of work to use radius arms when with the same amount of effort you could have a bind-free and caster-controllable 3-link.. whatever though. Looking forwards to how it performs.

 

[White Stripe]

Converting a 60 front to radius arms seems like a great idea. I would probably look into Bronco radius arms though rather than 80 arms. Bronco arms seem to allow a ton of flex and their are a ton of aftermarket options.

 

[Beams37]

On my 60 I'm trying out some of these concepts. In the rear I've swapped in a late 80 series rear axle along with SOA and 63" Chevy springs. A traction bar will be added to control axle wrap and a sway bar with quick disconnect links will be fitted. Up front I've gone with 80 series radius arms, King coilovers, a Front Range 80-width axle housing, and Front Range knuckles with keyed steering arms. I'll be running 37's. Total lift is about 6". To get, hopefully, a better ride quality I am inverting the radius arms, but this will also serve to provide better clearance under the axle housing. This will be going to Rubithon this year, and hopefully it is the good compromise between a trail rig and an overlanding rig that I'm hoping for. This work is being done by the good folks at Valley Hybrids. (and yes the exhaust is being rerouted ).

View attachment 1672528 View attachment 1672530

This looks awesome. I'm excited to see how it plays out. Keep me in the loop!

 

[RustyNailJustin]

On my 60 I'm trying out some of these concepts. In the rear I've swapped in a late 80 series rear axle along with SOA and 63" Chevy springs. A traction bar will be added to control axle wrap and a sway bar with quick disconnect links will be fitted. Up front I've gone with 80 series radius arms, King coilovers, a Front Range 80-width axle housing, and Front Range knuckles with keyed steering arms. I'll be running 37's. Total lift is about 6". To get, hopefully, a better ride quality I am inverting the radius arms, but this will also serve to provide better clearance under the axle housing. This will be going to Rubithon this year, and hopefully it is the good compromise between a trail rig and an overlanding rig that I'm hoping for. This work is being done by the good folks at Valley Hybrids. (and yes the exhaust is being rerouted ).

View attachment 1672528 View attachment 1672530

Interesting concept and awesome parts. Got any pics of how you packaged the coilovers?