I just got some HKS progressive rate springs with a 23mm front drop, and 13mm rear drop. They each come with thier own set of tested numbers attached to each individual coil, but I'm a bit foggy on the description of the rate. Here are the basic measurements for front and rear:
front - 1-2K , 2.65 kgf/mm; 2-3K , 4.58 kgf/mm
rear - 1-2K , 2.08 kgf/mm; 2-3K , 3.76 kgf/mm

What exactly is 1-2K and 2-3K? a length?
And what does kgf/mm mean? kilogram something per millimeter?
If anyone has the same type of measurements for other springs or even stock, I'd like to know what they are for comparison. Thanks!

Forgot to say this is on a 2nd gen. oops

 

kgf/mm = kg of force per mm = 55.88 lbs/in

I'm not exactly sure what the ranges refer to.

 

Thanks for the info! I'll do some more searching on the other rates.

 

Maybe they are progressive springs?

-Max

 

They are progressive, I'm just not sure what HKS means with those figures.

 

After converting to lbs/in they seem to be a little stiffer than all the other progressive rate springs from start to finish. Only in rough comparison though, other spring rates weren't perfect measurements. Can't wait to get them on!