What does it mean for a spring to be 52"?

[Mastiff]

I've been reading a bunch of threads but can't get this basic info. If a spring is a 52" spring, does that mean it's supposed to be 52" eye to eye when laying on the ground (no load)? Or is it 52" when under load? Or is it just a designator with no fixed relationship to stuff you can measure? I ask because I'm questioning the 4" Rancho lift springs I have on my K5. They measure 48" when not under load. Is it possible I've had the wrong springs installed for 15 years?

 

[tRustyK5]

Spring lengths are measured from eye to eye when the spring is flat...or lay the tape along the arch of the spring.

Stock spring lengths are 52" rear, 47" front...some pick-ups got 56" rears.

In theory any lift spring should be longer than stock to compensate for the extra arch, but that is rarely the case with kit lift springs, unless the lift is quite large (more than 6-8")

Rene

 

[Mastiff]

In theory any lift spring should be longer than stock to compensate for the extra arch, but that is rarely the case with kit lift springs, unless the lift is quite large (more than 6-8")

Interesting, so generally the more lift, the closer the straight line eye to eye distance? This could explain why I'm having a kind of a hard time getting my 4" lift springs installed (trouble getting the shackle flat enough). They eyes are closer together than they are for people with no lift or a lift-block setup.

 

[tRustyK5]

If you look at stock springs you'll see they are close to flat at ride height, and even unloaded don't have much arch...so yes a lifted spring can be a pain to install if it has a lot of arch.

Best thing is to break out the tape measure and run it from the center of one spring eye, along the arch of the spring to the center of the other spring eye and confirm it's a 52" spring.

rene