Unicorn lift kit?

[TbumOBS]

You can run 33s on reasonable wheels without any lift, I had 33s on my truck for 10 years and all I did was crank it to level.

There's no kit that will add travel to these trucks, a 4-6 lift kit will keep your suspension the same, just moved further down with brackets.

Those "key" lifts are a scam, they will ruin your front end and rattle our your fillings.

Long/mid travel IFS kits don't exist for these trucks, anything like that will have to be a from-scratch custom and probably cost more than the whole truck.

SAS is the only way people add travel to these trucks, but it's pretty overkill for 33s I think.

All I’m looking to do is clear 33x12.5 tires, can that be achieved by just cranking the stock keys?

 

[boy&hisdogs]

All I’m looking to do is clear 33x12.5 tires, can that be achieved by just cranking the stock keys?

Yeah I had 305/70/16 on my truck with just a crank and trimming the valence a little and bumper just a hair. It depends on how wide your wheels are and how much backspacing/offset. The more they poke out, the more they might rub. My wheels were pretty mild, 16x8 with 5" BS.

This is how they looked.

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[kylenautique]

Here's what I did, and what I recommend. I'm running the Rough Country 6" lift kit without the extra leaf spring and 33 inch tires (285/75R16). The 4" and 6" kit are the same. You just crank up the truck front end as needed and add the extra leaf spring in the back for 35" tires. I'm running 33" tires and the lift configured at 4". It rides like a caddy. People give the RC shocks a bad wrap, but honestly, they ride pretty darn nice. Now, here's the pro tip... Install the ReaLift torsion bar relocate adapters. They put the torsion bars back into the stock location so they don't hang down below the frame.

https://www.roughcountry.com/product/configurable/gm-suspension-lift-kit-276

https://www.realiftsuspension.com/

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[kylenautique]

Here's some install photos of the relocaters. You use your stock torsion bar mount, but you move it back a tiny bit. Its a simple install.

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[boy&hisdogs]

Here's what I did, and what I recommend. I'm running the Rough Country 6" lift kit without the extra leaf spring and 33 inch tires (285/75R16). The 4" and 6" kit are the same. You just crank up the truck front end as needed and add the extra leaf spring in the back for 35" tires. I'm running 33" tires and the lift configured at 4". It rides like a caddy. People give the RC shocks a bad wrap, but honestly, they ride pretty darn nice. Now, here's the pro tip... Install the ReaLift torsion bar relocate adapters. They put the torsion bars back into the stock location so they don't hang down below the frame.

https://www.roughcountry.com/product/configurable/gm-suspension-lift-kit-276

https://www.realiftsuspension.com/

You must be registered for see images attach

I agree this is the best (coolest and most clearance) way if the budget allows, although I'd be mindful of what gears are in the truck before anyone does this. I had 3.42s in mine stock, and that transmission was working HARD with those 33's in the hilly area where I lived, constantly shifting between 3rd and 4th on the road. A lift would have made it even worse. 3.73 would probably be fine though.

That being said a lift eats into your highway mpgs a lot due to the wind resistance. I went from 16-ish mpg stock to 10 when I lifted mine. I went a full 6" with 37s and 4.88s though, I imagine 4" and 33s would be a bit more reasonable.

If you don't want to lift, you can clear a skinny 33 with just a mild crank and modest wheels. I had both 285/75/16 and 305/70/16 before the lift, and to be honest I gained nothing from going to the 305 except some extra weight for my truck to spin.

+1 to the tortion bar relocators. Mine have been on my truck for a few years and about 20-30k miles if I'm remembering correctly, no issues so far.

 

[1998_K1500_Sub]

Now, here's the pro tip... Install the ReaLift torsion bar relocate adapters. They put the torsion bars back into the stock location so they don't hang down below the frame.

Interesting adapters. They nicely move the bar up and out of sight.

They’ll cause that end of the torsion bar (control arm end) to travel in an arc that’s a tad different from stock, as the LCA travels through its range of motion.

Not saying it matters (and not saying it doesn’t), it’s just an observation.

 

[KansasOBS]

Here's some install photos of the relocaters. You use your stock torsion bar mount, but you move it back a tiny bit. Its a simple install.

You must be registered for see images attach

You may not run into issues, but they say to cut a piece of PVC to use as a spacer for the shaft that goes into the arm. Or at least mine did.

Interesting adapters. They nicely move the bar up and out of sight.

They’ll cause that end of the torsion bar (control arm end) to travel in an arc that’s a tad different from stock, as the LCA travels through its range of motion.

Not saying it matters (and not saying it doesn’t), it’s just an observation.

You're not wrong. I dunno the rate difference if any, but I'm running 04 2500HD bars in my 98 3500 with these, everything seems to ride well.

 

[1998_K1500_Sub]

I dunno the rate difference if any, but I'm running 04 2500HD bars in my 98 3500 with these, everything seems to ride well.

It won’t change the rate any, interestingly, as the “twist” on the torsion bar remains unchanged through the LCA’s range of motion.

This might seem counterintuitive.

See “Moments Can be Placed Anywhere” on this webpage:
https://www.mem50212.com/MDME/MEMmods/MEM30005A/moments/Moments.html#:~:text=Moments Can be Placed Anywhere,always giving the same answer.

 

[rzr6-4]

It won’t change the rate any, interestingly, as the “twist” on the torsion bar remains unchanged through the LCA’s range of motion.

I think you are confusing a few things here. Slow day at work so let's try to break this down.

When saying that the torque transmitted through the torsion bar is unchanged, you seem to be referring to this diagram in your link:

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While I agree with the math throughout this example (of course I do, because I can't just disagree with physics), the KEY CONSIDERATION here is that your tangential distance, the distance between your rotating axis (nut) and your force's line of action is always the same, in this case 120mm. All this example is really demonstrating is that your Fx and Fy components will always add to the same resultant moment as long as your force continues moving through the same straight line.

In our trucks, the torsion bars acting through the control arm are more accurately represented by example 4, further down the page:

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This is just an upside-down version of control arms as they go through travel. In this case, instead of your tangential distance being a constant, it is now a function of "d" (or your control arm length) and it's angle as it rotates (Θ) around your pivot point (control arm mounting bolts), where your new tangential distance is calculated by the equation d*cos(Θ).

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Here is a quick sketch to show what I mean. The solid lines are our 18" control arm shown through 30 degree increments, and the dashed rectangles are our 33x10 tire going up and down through an arc. With the tire drooped down to the red position, just about to lift off the ground, lets say there are 200lbs on it. This is acting at an effective radius of 9", so 200lb * 9" = 1800lb*in being resisted by the torsion bar.

In our blue position, we have put some weight back on the wheel, we are just cruising down the road with 1270lbs on that tire. That 1270lb * 15.59" = 19,800lb*in on the torsion bar.

In our green position, we are now trying to drive our lead tire up onto something. A curb, large rock, downed tree, ex-wife, whatever. With that extra compression on that corner, we now have 2000lb * 18" = 36000lb*in

While I am taking some liberties here with guesstimations and numbers to make the math easy, you can look at my resultant torques and compare them using a constant torsional spring rate of 600lb*in / degree. This torsional rate would then imply/require that we add force as we travel through our range of motion, contrary to your point.

Another scenario: First off, remove all sway bars. Now, let's say we are turning right. As we turn right, weight is transferred to the left side, and unloaded from the right. If the torsion bars were putting out a constant torque through their range of motion, the truck would just flop over to the left side because if your springs are always in equilibrium, they won't actually do anything to counteract your uneven roll force. In reality, when force is transferred to the left side, your left torsion bar compresses more, increasing force all while your right torsion bar unloads, decreasing force. These uneven forces push the body back to the right, allowing things to balance back out. The idea that "the “twist” on the torsion bar remains unchanged" would not allow for these uneven forces, and thus the suspension would be completely unable to keep the vehicle upright, minus the presence of sway bars (and the rear suspension being different of course).

Ok, 'tism rant over. Need to put all of those physics classes to work somehow. Hopefully that all made sense.

 

[1998_K1500_Sub]

I think you are confusing a few things here. Slow day at work so let's try to break this down.

When saying that the torque transmitted through the torsion bar is unchanged, you seem to be referring to this diagram in your link:

You must be registered for see images attach

While I agree with the math throughout this example (of course I do, because I can't just disagree with physics), the KEY CONSIDERATION here is that your tangential distance, the distance between your rotating axis (nut) and your force's line of action is always the same, in this case 120mm. All this example is really demonstrating is that your Fx and Fy components will always add to the same resultant moment as long as your force continues moving through the same straight line.

In our trucks, the torsion bars acting through the control arm are more accurately represented by example 4, further down the page:

You must be registered for see images attach

This is just an upside-down version of control arms as they go through travel. In this case, instead of your tangential distance being a constant, it is now a function of "d" (or your control arm length) and it's angle as it rotates (Θ) around your pivot point (control arm mounting bolts), where your new tangential distance is calculated by the equation d*cos(Θ).

You must be registered for see images attach

Here is a quick sketch to show what I mean. The solid lines are our 18" control arm shown through 30 degree increments, and the dashed rectangles are our 33x10 tire going up and down through an arc. With the tire drooped down to the red position, just about to lift off the ground, lets say there are 200lbs on it. This is acting at an effective radius of 9", so 200lb * 9" = 1800lb*in being resisted by the torsion bar.

In our blue position, we have put some weight back on the wheel, we are just cruising down the road with 1270lbs on that tire. That 1270lb * 15.59" = 19,800lb*in on the torsion bar.

In our green position, we are now trying to drive our lead tire up onto something. A curb, large rock, downed tree, ex-wife, whatever. With that extra compression on that corner, we now have 2000lb * 18" = 36000lb*in

While I am taking some liberties here with guesstimations and numbers to make the math easy, you can look at my resultant torques and compare them using a constant torsional spring rate of 600lb*in / degree. This torsional rate would then imply/require that we add force as we travel through our range of motion, contrary to your point.

Another scenario: First off, remove all sway bars. Now, let's say we are turning right. As we turn right, weight is transferred to the left side, and unloaded from the right. If the torsion bars were putting out a constant torque through their range of motion, the truck would just flop over to the left side because if your springs are always in equilibrium, they won't actually do anything to counteract your uneven roll force. In reality, when force is transferred to the left side, your left torsion bar compresses more, increasing force all while your right torsion bar unloads, decreasing force. These uneven forces push the body back to the right, allowing things to balance back out. The idea that "the “twist” on the torsion bar remains unchanged" would not allow for these uneven forces, and thus the suspension would be completely unable to keep the vehicle upright, minus the presence of sway bars (and the rear suspension being different of course).

Ok, 'tism rant over. Need to put all of those physics classes to work somehow. Hopefully that all made sense.

One can apply a vector moment anywhere on body and it’ll have the same effect.

The angular displacement of the torsion bar remains unchanged by the relocation imposed by the adapter.

I’ll treat the adapter as simply an extension of the lower control arm, because I want to focus on the torsion bar.

The adapter does relocate the bar’s point of connection, which does alter the location of that endpoint of the bar as the LCA moves through its range of motion. If those changes (“relocations”) are small compared to the length of the bar, and the bar is free to move at its opposite end, then I am willing to dismiss them. (Edit) Too, with this assumption, the moment vector direction is unchanged from the original.

This is mostly 100-level college stuff, at least when I was in school, Theoretical and Applied Mechanics 154 in my case, which came after the physics sequence 106, 107 & 108