TORSION BAR ADJUSTMENT
On a Chevy site. You have what 4 Mopars? Take your choice and jack the thing up and crank the bars up fairly close to the top and go for a drive. Dang right it rides like a lumber truck.
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So, you went to a Chevy site to get accurate information on a Mopar torsion bar suspension? Well, surprise, it's wrong. Not to mention, how do you know that guy is right even for a Chevy style torsion suspension? Preload on torsion bar systems is very different than on a coil spring system, and a lot of people try to apply what they know about coil springs to torsion bars.
The preload on a Mopar torsion bar suspension comes from the weight of the car. This is not like a coil spring suspension. You aren't adding preload by cranking up the torsion bar adjusters. Take a look at a lower control arm. When you turn the adjusting bolt, it changes the angle of the control arm with relation to the torsion bar lever. It does not twist the bar, it just changes the angle of the LCA with regard to the hex. That's one of the biggest advantages to a torsion bar suspension- you can adjust the ride height
without substantially changing the preload. It's also how the offset on the bar sets the ride height range, and why the offset has to be different as you increase the diameter (spring rate) of the bars.
The ONLY difference comes from the effective length of the "lever" between the lower ball joint and the torsion bar hex. I've calculated that difference at the extreme ends of the suspension travel, you're talking about a few lbs/inch on the wheel rate, which means you're not talking about a substantial preload difference.
I'm not saying your car didn't ride like crap jacked up in the air like that, I'm sure it did. But it's not because you changed the pre-load or wheel rate significantly, it's because you eliminated the suspension travel on extension and hammered the alignment specs.
IMHO, there is a reason for the factory specific ride height adjustment parameters. They were helping us to get the best ride possible.
With bias ply tires.
The factory specific ride height adjustments were based on the handling characteristics of bias ply tires. So are the factory alignment specs. The camber curves, bumpsteer, amount of caster, etc are all completely different from bias ply tires to radials.
If you install radials, the factory ride height adjustments do not give you the best suspension geometry. It's just like using the factory alignment specs for radial tires, except your applying it to the full range of suspension travel. What worked best for ride height and suspension geometry from the factory is totally different than what works best once you install a set of radials.
