Ummm, no. I think you may have your definitions messed up here. A fixed rate spring is a spring that requires a FIXED amount of force to deflect the spring every given unit of length (this is also referred to as "linear-rate"). Correct me if I am wrong, but the rates you posted are just a tolerance band that the spring rate will be in for Sportlines. While the spring rate may vary as the spring is deflected, it will not vary much within this band. This is all opposed to a progressive-rate spring (e.g. Pro Kit) where the force required to deflect the spring will vary to a completely different tolerance band based on how much the spring has already been deflected.
Ummm, no. I think you may have your definitions messed up here. A fixed rate spring is a spring that requires a FIXED amount of force to deflect the spring every given unit of length (this is also referred to as "linear-rate"). Correct me if I am wrong, but the rates you posted are just a tolerance band that the spring rate will be in for Sportlines. While the spring rate may vary as the spring is deflected, it will not vary much within this band. This is all opposed to a progressive-rate spring (e.g. Pro Kit) where the force required to deflect the spring will vary to a completely different tolerance band based on how much the spring has already been deflected.
So what you saying is that with linear rate spring, it takes SAME amount of forse to compress spring from its most relaxed position(?i guess) to compressed to the point it nolonger compress. right?
And basicaly,progressiverate is more you compress the spring, more force you need to continue. Right?
in Eibach's web site, it sais that Sportline is preogressive spring sesign tho... read this
EDIT - ahhh it wont link. here
"Created for the extreme enthusiast, who wants that "race-car" attitude, our Sportline springs are designed for maximum street performance - with the lowest possible drop. Engineered with the same care as our Pro-Kit springs, Eibach's Sportline springs achieve legendary handling by aggressively lowering the vehicle's center of gravity with precision-engineered spring rates. The results is a car that handles as well as it looks. Eibach also offers top-quality Alignment Kits to keep proper suspension geometry.
As with our popular Pro-Kit, Sportline springs are designed by experienced suspension engineers and manufactured using the finest alloy spring wire available and under the same Eibach quality standards.
* Extreme Performance
* Race-Car Like Handling
* Progressive Spring Design
* Lowers vehicle 1.75" to 2.25"
Sportline puts it all together, Race-Car looks, sportive handling and Eibach proven quality."
I don't know.... All i know is that progressive is better on ride confort, because it is softer unless you compress the spring more....