If I change springs then I'll test them to see if the manufacturer was close when they spec'd them.

Regarding wheel rate you are correct! My numbers were based on the wheel rates of my SC10 using my electronics & my battery mounted all the way forward. Moving/changing any of these can & most likely will change wheel rate.

Here is what is weird. According to the formulas I found the wheel rate went up when the shock was angled more. This in turn increased the spring frequency using the calculation I found to determine that. I'm scratching my head trying to figure that one out. Must be something I'm doing wrong.

In an ideal world we can measure things, put them into cookie cutter formulas and model an expected result. I think Fred is trying to tell us not to do that but to 'bench test'. Being I'm totally left brained and analytical I'm always searching for a mathematical equation.

This is an interesting thread!