Coil Spring Rates

[Road Ruler]

I want to replace my rear springs by going to a higher rated spring but I do not want to lower the car.

I have heard, or read somewhere?? that the X sedan has firmer rear coil spring. Does anyone have the OEM spring rate numbers available?

Thnxs for any info

[Q45tech]

Spring rates have very little to do with handling other than body roll which has even less. to do with handling. The problem is all the forces pivot around C of G [the midpoint of trackwidth].

Assume a 15 " free unmounted length with 123 pounds per inch of compression the body weigh [say 900 pounds] compresses the spring by 900/123 or 7.317"...............the body lowers on the spring by ~~ 1/2.

The free length AND the stiffness must be complementary to not change the ride height.

G springs are not mounted close to wheel but in ~~ midpoint of suspension arm which means they have to be ~~ 3-4X stiffer since the arm movement is divide by 3-4 times..............a 1" wheel movement only moves the spring by 0.25-0.33".

[Road Ruler]

Good info Q45 and I understand but I am using the G as a part time Tow Vehicle for an RV (trailer) and I am getting more sag on the rear than I need. A stiffer spring will help prevent excessive sag.