Ride Height Restored!

[66 Sat]

Surely Kern Dog is correct here, at least that's how I've always viewed it too. The rear of the bar is fixed (i.e. the hex doesn't turn), and the front gets rotated by the adjuster, putting more "twist" on the bar.
As the suspension goes up or down the twist increases or decreases, but the starting amount of twist is dictated by the adjuster position.
Is this not the case?

 

[dadsbee]

No, initially it twists to pick up the weight, after that nothing twist wise changes even if you could lift it another 6 inches.

 

[eldubb440]

 

[nitro_rat]

Surely Kern Dog is correct here, at least that's how I've always viewed it too. The rear of the bar is fixed (i.e. the hex doesn't turn), and the front gets rotated by the adjuster, putting more "twist" on the bar.
As the suspension goes up or down the twist increases or decreases, but the starting amount of twist is dictated by the adjuster position.

The bar is anchored at one end, the clocking of the "anchor" on the other end is rotated by the adjuster. In the picture below, see how the tip of the adjuster bolt isn't touching the "hex pivot"? The control arm basically rotates around the torsion bar adjuster. When you crank the screw you're just setting the starting position of the anchor in relation to the lower control arm.

The bar's position in relation to the X-member end anchor never changes, and the rate of the bar doesn't change. Assuming the weight of the car remains the same also, the bar will rotate "up" the same number of degrees for the same applied weight, no matter what the starting position is.

Now, since the arm is a fixed length, it is "shorter" at the extreme "up" and "down" positions, so it has less leverage on the bar when cranked full up or down. When the arm is clocked dead level under tension (at ride height) it is longest and therefore exerts more leverage on the bar, making the "felt spring rate" less, i.e. softer ride.

 

[nitro_rat]

Here's a crappy artist rendering of 3 different control arm settings. The first one is "slammed", the second one is mid height, the third is "full crank." The 3 arms on the left are unloaded - car on jacks. The 3 arms on the right are loaded - weight on the wheels. The black line is the control arm, the gray line is the imaginary continuation of it's angle across the same arm in its opposing condition.

The bar rotates up the same number of degrees from the starting point, so angles A, B, and C are the same.

It's a crappy sketch I made in paint, don't criticize it too much please...

 

[eldubb440]

 

[68 Sport Satellite]

The bar is anchored at one end, the clocking of the "anchor" on the other end is rotated by the adjuster. In the picture below, see how the tip of the adjuster bolt isn't touching the "hex pivot"? The control arm basically rotates around the torsion bar adjuster. When you crank the screw you're just setting the starting position of the anchor in relation to the lower control arm.
View attachment 1801588
The bar's position in relation to the X-member end anchor never changes, and the rate of the bar doesn't change. Assuming the weight of the car remains the same also, the bar will rotate "up" the same number of degrees for the same applied weight, no matter what the starting position is.

Now, since the arm is a fixed length, it is "shorter" at the extreme "up" and "down" positions, so it has less leverage on the bar when cranked full up or down. When the arm is clocked dead level under tension (at ride height) it is longest and therefore exerts more leverage on the bar, making the "felt spring rate" less, i.e. softer ride.

this is a good explanation and the photo helps, thanks!

So in the case of using drop spindles, I'd always heard drop spindles will allow you to naturally drop the nose of the car and then the torsion bars won't feel as soft as if you were to just crank the torsion bars down to that same front ride height. Is this true? I'm confused because your explanation here makes it sound like the softest ride is actually in the middle.

 

[themechanic]

The bar is anchored at one end, the clocking of the "anchor" on the other end is rotated by the adjuster. In the picture below, see how the tip of the adjuster bolt isn't touching the "hex pivot"? The control arm basically rotates around the torsion bar adjuster. When you crank the screw you're just setting the starting position of the anchor in relation to the lower control arm.
View attachment 1801588
The bar's position in relation to the X-member end anchor never changes, and the rate of the bar doesn't change. Assuming the weight of the car remains the same also, the bar will rotate "up" the same number of degrees for the same applied weight, no matter what the starting position is.

Now, since the arm is a fixed length, it is "shorter" at the extreme "up" and "down" positions, so it has less leverage on the bar when cranked full up or down. When the arm is clocked dead level under tension (at ride height) it is longest and therefore exerts more leverage on the bar, making the "felt spring rate" less, i.e. softer ride.

Hmmm?

 

[69conv]

I like the new height even if we don't know how it got there!

 

[nitro_rat]

this is a good explanation and the photo helps, thanks!

So in the case of using drop spindles, I'd always heard drop spindles will allow you to naturally drop the nose of the car and then the torsion bars won't feel as soft as if you were to just crank the torsion bars down to that same front ride height. Is this true? I'm confused because your explanation here makes it sound like the softest ride is actually in the middle.

A drop spindle moves the location of the center line of the wheel up with everything else staying the same. Due to the nature of suspension geometry there can be some unintended consequences. Sometimes it is noticeable, sometimes not so much.

There are some areas of geometery like where in the caster line (line beween upper and lower ball joint) the spindle is. Sometimes a drop spindle throws this off because if you moved the spindle up the line, the wheel would go backwards in the wheel well. Sometimes it's not enough to matter. Kingpin inclination and some other stuff can get messed up too, it just depends on the thought that went into the particular spindle and how much the drop is.


You may also potentially end up with less ground clearance at a given ride height.

The center is stock height suspension. On the left is lowered suspension, on the right is lowered roughly the same but with a drop spindle. The green line represents the lower control arm mounting point to the chassis. Notice how much closer the ball joint end of the control arm is to the ground with the dropped spindle. Sometimes this can lead to "scrub line" issues, where the lowest part of the chassis is lower than the bottom edge of the wheel. This is illegal in most jurisdictions because the chassis would dig into the road surface in the event of a flat tire. A larger diameter rim can sometimes overcome this, also other clearance issues as the ball joint, tie rod connection point, etc. may be inside the hoop of a 20" rim where they might be rubbing the sidewall of the tire on a 15" rim.

I don't know anything about drop spindles on Mopars specifically. I used to do some sport truck stuff and they usually caused more headaches than they are worth.

I would definitely stay away if I was in to handling stuff, maybe okay if it's just a cruiser. That's my 2 cents and it's worth what you paid for it...

 

[Kern Dog]

It does not. The length the bolt is threaded out dictates the height, bar doesn't twist anymore than it already was supporting the existing weight.

If you crank the screw with the weight of the car on it this is true - until you roll the car and release the stored energy...

Exactly, you're just changing the clocking of the hex at one end of the bar relative to the position of the rest of the vehicle.

How is it that with the adjuster screw backed off, the control arm can be removed easier? It is because the tension is removed so it isn't in a bind.
The more you tighten the screw, the more it adds leverage on the bar. How could it be that the bar doesn't meet that leverage with some manner of resistance? A thicker bar tolerates fewer turns from the screw before raising the car, a thin bar tolerates more turns before raising up.
I'm interpreting that some think that that if you paint a line on the bar parallel with the length, that the line will remain straight no matter the ride height. While I have never tried that, I wonder how that could be. It sure seems (in theory) that if two cars are on their wheels and adjusted to sit as tall as possible, that the car with thin torsion bars will show more twist than the one with thick bars.

The bar is anchored at one end, the clocking of the "anchor" on the other end is rotated by the adjuster. In the picture below, see how the tip of the adjuster bolt isn't touching the "hex pivot"? The control arm basically rotates around the torsion bar adjuster. When you crank the screw you're just setting the starting position of the anchor in relation to the lower control arm.
View attachment 1801588
The bar's position in relation to the X-member end anchor never changes, and the rate of the bar doesn't change. Assuming the weight of the car remains the same also, the bar will rotate "up" the same number of degrees for the same applied weight, no matter what the starting position is.

Now, since the arm is a fixed length, it is "shorter" at the extreme "up" and "down" positions, so it has less leverage on the bar when cranked full up or down. When the arm is clocked dead level under tension (at ride height) it is longest and therefore exerts more leverage on the bar, making the "felt spring rate" less, i.e. softer ride.

Thanks for the effort but this explanation went WAY over my head.

Hmmm?

View attachment 1801617

Yeah...me too.
Again, I'm trying to stir the pot or bullshit anyone, I'm just having a hard time seeing how it could be different. This reminds me of that GIF that had a spinning female dancer that some thought was turning clockwise while others thought CCW. It seems hard to prove either point.

 

[dadsbee]

Don't know what else I can say, see post #22. No different than a coil spring, set a 1000 lbs on it and note it's compressed height. Now lift it all higher off the ground, the spring compressed height doesn't change. No different than twisting a torsion bar...

 

[AR67GTX]

The bar twist remains constant if the weight is unchanged. The height is based on the adjuster setting which positions the LCA with respect to the hex socket the bar is engaged in.

With that big of a change up front, the OP might want to back the nuts off on the LCA shafts, bounce the front a few times or drive it around the block to let the bushings relax to the new height setting and then re-tighten them.

 

[Fran Blacker]

 

[Kern Dog]

Okay...I have a low wattage "light bulb" moment...
I was forgetting for a moment that the LCA moves up and down while the torsion bar socket in it remains in the same relative position.
The LCA moves, the torsion bar and socket stay in mostly the same "clocking".
Why couldn't anyone else explain it this way? Was this the road I had to go down on my own ??

 

[RemCharger]

I have a control arm in a k frame at the shop and I was going to do some pictures but then I thought HEY! I gotta get this truck done lol..
.. a '12 F150, with a 3.7 V6.. don't recall seeing one before. Basically an Edge motor

 

[pnora]

Okay...I have a low wattage "light bulb" moment...
I was forgetting for a moment that the LCA moves up and down while the torsion bar socket in it remains in the same relative position.
The LCA moves, the torsion bar and socket stay in mostly the same "clocking".
Why couldn't anyone else explain it this way? Was this the road I had to go down on my own ??



View attachment 1801669

You had these on.

 

[nitro_rat]

View attachment 1801625

clockwise

 

[Kern Dog]

clockwise

Ha! Look at it, close your eyes, unfocus and look again.
It keeps changing for me.

 

[R413]

Now I see it!