Sway Bar Rate Calculator- shows you the spring rate of a sway bar:
Posted in another forum by Billy Shope:
If you're using a torsion bar and arms from a place like Speedway Engineering, the calculation for rate, at the end of the arm, is very straightforward:
rate = 1.139E6*D^4/(A^2*L)
where the "E6" indicates the true decimal point is located 6 spaces to the right, the "^" indicates exponentiation, "*" is multiplication, "D" is the diameter of the bar, "A" is the length of the arm, and "L" is the length of the bar.
Unfortunately, with an OEM bar, you simply have to make a reasonable estimate for some of the dimensions. In addition, some OEM bars have additional "jogs" in them. There are ways to get around these problems with an acceptable error, but they're beyond the scope of a short post like this."
A LOT of chassis info: