Hey there,
With torsion bars, it is easy to determine what is going to be firmer....Just compare diameters. A 1.24 is going to be stiffer than a 1.0.
With leaf springs, how do you determine the rate? Common sense tells me that leaf thickness, width and the amount of leafs in the pack are a big factor but are there different rates of the spring steel? The car I have is a '70 Charger.
In 2006 I installed Mopar Performance 440/Hemi spec XHD leaf springs even though I do not drag race the car. I wanted something firmer than a 318 car would have had. I currently have 1.15 torsion bars in the car. I was just curious as to how the leaf spring rate is determined.