Well, it worked. Torsion bar sway bar and PMF radius arms eliminated rub on 37x12.5’s with no lift or wheel spacers on OEM wheels.







PMF radius arms would not permit quite stock caster:

before (OEM):





After (including pic of bolt hole difference at max adjustment of PMF):

 

Do you have the part numbers for both parts?

 

PMF Radius arms:
Adjustable 3-Link Arms

sway bar parts (arms and bearing/bushing mounts) were custom made. I want to give it a bit of use before recommending - and I think the bearing mounts could be closer to the frame and contoured to be higher clearance without any interference.

 

But at what cost $$$$?

 

About $1200 shipped for the radius arms and same again for the sway bar. Sway bar should be a fair bit cheaper in future iterations; there was a lot of time in on figuring out how to make it come together despite the end result being fairly simple.

every time I bring this effort up I make sure to put on my flame retardant vest...

 

Looks great, I wish my wife was a bit taller so I could do the same. I am thinking of dropping it 2 inches so the 275-70 r18's look like that inside the fenders.

 

It looks awesome

 

That sway bar looks sweet dude, give us some more details!

 

Awesome work! Did the PMF arms not allow stock castor because they’re built for a leveling or lift kit?

 

Very cool. Glad someone figured it out

 

tell us more about those jackstands/jacks

How do the tires do on highway and off?

Love the ingenuity

 

$2,400 to eliminate the 1/4" worth of rub on 12.50's with no lift or level? I commend you for your efforts.

 

Exactly what I was thinking. OP must really love those stock wheels.

 

Hah, I’m glad he did it and appreciate the exploration required. Now we all know what it takes and it looks great for those who want big rubber and still need to get in to the garage.

 

35”x1.25” splined torsion bar, arms made out of 5/8 steel. Sealed bearings instead of bushings. The bearing brackets and arms are the custom part.

Bushings would probably be fine for a truck but once we went this far I figured why not do it all right. This style of sway bar might look odd if you haven’t seen them before, but this is a higher performance (stiffer, no slop) system than a single piece.

After a few hundred miles I’m very happy with it. On the softest setting it feels same stiffness as stock. Off road and in potholes it still flexes nicely (not too stiff). I think my only real change in a subsequent iteration will be to put the bearings closer to the frame.







they are supposed to be adjustable down to stock without a lift or level. I suspect it’s because I don’t have plow springs - their minimum adjustment would probably be right for about an inch more up front. Regardless, 4-5 degrees of caster feels great on these trucks so the minor increase isn’t bothersome.

They sell those at tractor supply and on amazon. I’ve got a few of them - I find the bottle jack /jack stand combo is nice. Very stable base. Great for work like this to be able to raise/lower the axle and frame on either side without maneuvering anything.

tires are very smooth on highway. Slightly louder than stock but not as loud as the duratracs on my gen 1 super duty. No vibrations - drives perfect 75-85.

Beyond a good cellphone mount and steering stabilizer there’s not much everyone should be doing to their super duty. Like I said earlier every time I bring this up I put my flame retardant vest on first... it’s clear me wanting to keep tires as far inboard as possible puts me in the minority. Eliminating rub with wheel spacers or wheels with -20 offset is well covered ground here and are great options. Living with rub is also a perfectly fine option; I did about 6,000 miles that way.

I likely will at some point raise the front 1-1.5” (need some rake; truck gets worked). The radius arms will allow me to keep caster perfect and avoid rub that would have been a factor then too. Doing things incrementally means I know how each thing impacts the ride. I even kept stock tires and wheels around ready to go back to Incase I had ride quality gremlins after 37’s. Truck drove 85 today just as well as it did bone stock!