steering and suspension Coil over spring rates

[doug73cs]

I have been in discussion with two providers on 8" coil over spring kits to replace my ST front springs for my 73CS.  Both are in agreement with the replacement spring rates - 300 to 325ft/lb to replace the ST springs 265ft/lb.  I don't want a significant change to the stiffness as much as the ability to adjust the ride height.

 

I'm curious as to why higher rated springs for coil overs?  

 

Any informed advice on this appreciated.

 

Doug 

[TobyB]

As you suspect, there's no reason- a spring is a spring is a spring.

As long as it's in the same location with the same geometry... sometimes that's not the

case in the rear, where the 5" spring is compressed just a little bit differently than a

2.5" spring...

 

That said, 265 to 300 isn't a big jump- maybe they can't source a 275 lb/inch spring.

 

The other nice thing about coilovers is that if you think it's a bit too stiff or soft, or that it

pushes or is tailhappy, all you have to do is get another set of relatively inexpensive springs.

It's a very easy way to tune a suspension pretty precisely.

And the springs you end up not needing are a standard commodity, so they're easy enough

to sell or pass along to someone else.

 

t

[cj]

As a spring is compressed, the force to compress the spring increases. The ST spring, when compressed to 8" height is likely in that 300lb range.

Edited December 6, 2014 by cj

[jrkoupe]

how long is the ST spring?......is it a linear spring?..or progressive?

this is a follow up to cj's response.....

[allbim]

In the US of A, a spring rate is the amount of change in force you need, in pounds, to change the spring length by 1 inch .

In other words, if you're compressing a spring one inch, and the required force is 300 pounds, then you have a 300 pound per inch spring.

Another inch of compression would then require an additional  force of 300 pounds, for a total of 600 pounds and so on.

This applies to linear springs only.

From what I recall, a stock front spring on a 2002 is 180 lbs/inch.

[TobyB]

 

 

As a spring is compressed, the force to compress the spring increases. The ST spring, when compressed to 8" height is likely in that 300lb range. 

This is not true of a linear spring that is not in coil bind.

 

The 2002 ST springs are linear- but I dunno about the CS version.

 

t

[doug73cs]

Thanks to all - question answered. The springs in the CS are the same configuration as the '02 - as in linear.

Doug