[ckucia]

I was playing with some suspension ideas in my head last night...

Lets say you were building a rod that is going to incorporate adjustable coilover front springs that are outboard of the control arms (so you have more freedom on the mounting points just for the sake of discussion).

As I understand it, the adjustability of the coilovers can change the ride height, within reason, but this doesn't affect the spring rate unless you swap in different coil springs.

My question is, if you change the mount points of the spring so that it acts at an angle (on the same plane as the angle through which the control arms move, not front to back), rather than straight up and down, do you alter the effective spring rate?

Seems like the force exerted by the spring at an angle would become close the sine of the angle from vertical multiplied against the force the spring exerts straight up and down.

In other words, the more angled the spring is from vertical, the "softer" it would act on the suspension vertically (and the more it would stress the mount points horizontally).

Am I understanding this right?

BTW, I understand that the angle in question isn't really fixed as it is going to vary somewhat due to the arc through which the control arm travels changing the horizontal position of the lower mount point, but at ride height, the comparison should be pretty close. Also, by angling the spring, you would lose proportionally, some of the available spring travel.

[astroracer]

Everything you mentioned has an effect on spring rate, motion ratios and the end effectiveness of the shock/spring package. Read through the following links. Tons of good info in the Afco link and the proshocks site will give you an idea of what shock placement does to spring rate. Use the calculator with a grain of salt though. It doesn't allow you to input the upper shock point so there is no way to really calculate a true spring rate without knowing the shock angle.
http://www.afcoracing.com/tech_pages/index.shtml
http://www.proshocks.com/calcs/imotion.htm
This is a chart to correct spring rate when angled shocks are involved.
http://www.proshocks.com/srshocks/tech4a.htm
Mark

[ckucia]

Thanks for those links, astroracer. They help a lot.