Flipping radius arms (1 Viewer)

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I follow a build from Australia and they just recently flipped the radius arms on his rigs. My meaning of flipped removed the radius arm mounts and installed them on the top side of the axle. Apparently doing so will allow for better articulation and caster.

Has anyone here in the states done something similar?

flipped radius.jpg


flipped radius 2.png
 
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I follow a build from Australia and they just recently flipped the radius arms on his rigs. My meaning of flipped removed the radius arm mounts and installed them on the top side of the axle. Apparently doing so will allow for better articulation and caster.

Has anyone here in the states done something similar?

View attachment 2578915

View attachment 2578919
Looking a interesting for sure
 
Something like this would be great for a dedicated crawling rig. Increased clearance and articulation. On the other hand getting that setup to drive down the interstate at 75 safley would probably take some mad skill and extensive use of an alignment rack.
 
Something like this would be great for a dedicated crawling rig. Increased clearance and articulation. On the other hand getting that setup to drive down the interstate at 75 safley would probably take some mad skill and extensive use of an alignment rack.
The person the did this mod in his post on IG @shawrry said that the caster was figured in when rewelding the mounts. Is that what you are referring to as far as alignment?
 
Your probably right about it in terms of caster.

There was someone else on the forum who did that, it’s an interesting mod and I plan to do that on my SD D60 swap in the next couple of months.

Mostly all you are gaining is clearance, but you may have interference with coil springs, you’d have to rebuild the spring mounts above the radius arms and use a shorter spring, or in most cases go to a coil over I’d guess. I wonder if they brought the arms inwards slightly in the pic.

Regardless, it’s more than a few hours of cutting, fab, and welding, and then new coils/coil-overs and maybe shocks.
 
The person the did this mod in his post on IG @shawrry said that the caster was figured in when rewelding the mounts. Is that what you are referring to as far as alignment?
I just meant that it would take very precise placement, measuring, and positioning to get the correct caster doing something like this. It would take more than simply cutting the mounts off the axle and welding them back on the top willy nilly. Without an alignment rack to measure different things and adjust accordingly it would be like pissing blindfolded and not splashing on the seat.
 
It's not that big of a deal. And with a bunch of lift makes great sense. Not just for caster but for bringing the geometry of the arms back. Obviously it can be done poorly, but this is one banana compared to custom link setups which are done all the time.
 
Something like this would be great for a dedicated crawling rig. Increased clearance and articulation. On the other hand getting that setup to drive down the interstate at 75 safley would probably take some mad skill and extensive use of an alignment rack.
What would happen, more specifically? (innocent question...looks very interesting)
 
Alignment rack? So, if you have a flat surface on the knuckle perpendicular to the pivot point, you can drop a digital angle gauge on it, rotate the axle with the radius arm brackets set on top, and when you get to your 3 degrees or whatever is ideal you tack them on then burn them in.

You probably want to pull the coils, have the frame sitting on jacks at whatever your ride height should be at, and roll the axles into place with the wheels and track bar on.
 
Alignment rack? So, if you have a flat surface on the knuckle perpendicular to the pivot point, you can drop a digital angle gauge on it, rotate the axle with the radius arm brackets set on top, and when you get to your 3 degrees or whatever is ideal you tack them on then burn them in.

You probably want to pull the coils, have the frame sitting on jacks at whatever your ride height should be at, and roll the axles into place with the wheels and track bar on.
I guess I don't know what I am talking about. Maybe we will see more people running this mod, especially if it is so easy.
 
I guess I don't know what I am talking about. Maybe we will see more people running this mod, especially if it is so easy.


Hmm. So, first, any comments or contradictions aren’t meant to be condescending or anything.

I think your concern about the alignment rack probably is coming from concern about driveability and safety, and that is totally valid.

Your toe in (or toe out) shouldn’t change, we’re not messing with the tie rod, or at least we shouldn’t be. So that should not be a factor, and is one of the important reasons for checking overall alignment.

Having your axle perpendicular to centerline of the frame is important, but if your fabricating (or waterjet or laser table) your brackets and they are all the same, sitting on the same tube, that shouldn’t be out by any significant measurement.

Camber shouldn’t be affected unless we’re bending the axle in the process some how.

Caster is the main thing we’re looking at when moving the arms to the top of the axle, and that is simply rotating the axle housing to tilt the pinion up or down more, but we’re doing it so that we find ideal caster, and the brackets can be welded in place when the ideal angle (I think it’s about 3*) is achieved.

There are some other things that could be considered in doing this work. Installing a DC shaft and pointing the pinion at the T-Case, and a cut and turn of the outer ends of the axle to get perfect pinion angle and camber. That would be more work but totally doable. Moving the axle forward for fender clearance for larger tires, and a longer and more stable (and weight balanced) wheelbase is also a gain. I would just redrill the stock frame bracket with a hole forward of the original for the upper end of the radius arm.


But... if your doing all this cutting and welding and crap. Well, upgrade your wheel studs from 6 of them to 8 of them, upgrade your brakes, upgrade your steering rod size and axle shaft size while your at it (just put in a one ton axle) and be done with it.
 
It's a great idea, Toyota should have done this originally...luv the clearance it gives!
 
A minimum of 4” lift is required to fit the arms comfortably above the axle. This is nothing new. I would suspect that this mod would move the axle forward a slight bight as the leading arm bolt holes line up with each other on a more horizontal plane. This would change the arc path of the axle as the suspension cycles, meaning that, as a front tire moves up into the wheel well it may also be moving rearward instead of forward as it did when the arm was below the axle. Forward movement under compression encourages traction. This feature is also a good reason to leave the shackle of a leaf sprung cruiser at the forward end of the front springs.
 
A minimum of 4” lift is required to fit the arms comfortably above the axle. This is nothing new. I would suspect that this mod would move the axle forward a slight bight as the leading arm bolt holes line up with each other on a more horizontal plane. This would change the arc path of the axle as the suspension cycles, meaning that, as a front tire moves up into the wheel well it may also be moving rearward instead of forward as it did when the arm was below the axle. Forward movement under compression encourages traction. This feature is also a good reason to leave the shackle of a leaf sprung cruiser at the forward end of the front springs.

The arc path depends on the pivot point (bolt hole at the upper mount on the frame), and if the radius arm is lengthened (by that I refer to where it is attached to the axle making it a straighter or rather longer link).

Arc radius is only the bolt hole for the radius arm and center of axle that your looking at, neither of those need to change but can, radius arm attachment point will not affect arc though if the other two points remain the same.

Not sure if you are saying this, it could be taken in different ways. I remember the argument years ago on the topic and had to think about it for a few minutes myself.
 
I had that on my rig, done by a previous owner. He put 7" springs on and made a mount to move the axle forward to center the front wheel in the opening. Long story short, he didnt do it right. I bought it for a decent deal, because the guy i bought it from didnt want to put the money into it to do it right. It had death wobble that wouldn't go away. I ended up getting a new (to me) housing that still had the oem mounts and delta arms. It was cheaper than having a shop re-do everything. Georg @ Valley Hybrids did an excellent job doing the swap. Drives sooooo much nicer now. Rock solid at 75mph on 37's with beadocks. I never saw the upside. There was a little more under axle clearance, and a lot of tie rod clearance. Thats about it. Maybe if it had been done right, I would have left it.
 

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