OEM Spring Rates

[tcheb]

I'm looking at stock ix springs and I see three different Part Numbers:

33539061136 (From 09/1988 Mtech)
33539061592 (From 09/1988 Up To 09/1989 )
33539058926 (Up To 09/1988 & From 09/1989)

I would need to know what is the difference between them: height? stiffness?

I actually need springs for a Euro 325ix Touring but those are NLA:
33539061400
33539061450 (with towing hitch)

I want to find out which ones would be the closest fit.

[nando]

the earlier ones may be stiffer as the earlier cars were heavier.

mtech are definitely stiffer but may also be slightly lower.

I don't think you'll find any reliable information on actual spring rates. there's a chart that people peiced together from around the internet, but the accuracy of the quoted rates is highly uncertain.

[tcheb]

Sounds like I may have to order several sets and then return the ones I don't want.

I did find several charts but they mostly covered aftermarket springs.

Thanks!