Its hard to get solid wheel rate info on the PST bars. Most claim there a bit softer than the ff 1.06? bars.
Good luck on getting a rate from PST. I tried for over a year, messaging them here and through their site. I gave up and bought a set of FFI 1.06's. Their loss.
Based on the 1.03" diameter and the "normal" spring constants for torsion bar type steel, you should be looking at a spring rate that's probably between 215 - 230 lb/in. Roughly. The listed rates vary by manufacturer, but that's a pretty decent ball park. Most of the 1" bars are around 200 lb/in, the 1.06's are usually around 250 lb/in, so, yeah.
I might be wrong in my thinking so correct me if I'm wrong, but typically cranking ride height into a t- bar suspension makes the ride stiffer. So I'm thinking wheel rate is function of preload, and why the results vary so much. I want it lowered, so I'll be on the softer side of that scale.
You're wrong. ;)
This is a common misconception. Adjusting the ride height does
absolutely nothing to the spring rate. Zilch, zip, nada.
It doesn't even change the preload under normal circumstances. That is a function of the weight of the car, and pretty much the weight of the car alone.
Take a look at your lower control arms. You can see that the torsion bar socket is connected to an adjusting lever, which is controlled by the torsion bar adjusting bolt. Most people think that turning the torsion bar adjusting bolt twists the torsion bar. It does not under most circumstances. It changes the angle of the LCA with respect to the torsion bar socket. Without the adjusting bolts in place, the LCA just rotates loosely on the torsion bar socket. The adjusters just hold the LCA in place at a certain angle.
So, why then does it get hard to turn the adjusting bolts if you really crank them down? There's only so much adjustment in the LCA when it's on the car. So, at some point, you max out the angle of the LCA with respect to the torsion bar socket, and you do start to place load on the torsion bar. But, the ONLY way to put more preload on the bar than is what is normally there with the car sitting on it's suspension is to completely exceed the force exerted by the weight of the car. IE, the suspension would not settle even a fraction of an inch with the weight on the wheels compared to no weight at all. Otherwise, even though you may have "preloaded" the bars some with the adjusters, the weight of the car is still more than that, and that will be your final amount of preload.
The only other way to change that would be to lower the car so much that the torsion bar adjusting bolts come out of the adjusting arms at full droop. With the car on it's wheels, you'd still have the car's weight as your "preload". But, if you hit a pothole and induced negative travel, the LCA would freewheel and there would be no load on the bars at all. Also- not good. But, as soon as the adjusters were back in contact, yup, you guessed it, same amount of preload.
So, under normal operation, the only thing that the torsion bar adjusting bolts change is the ride height (which does change your alignment numbers).
