All Eibach motorsport springs are tested between 20% and 70% of the spring's total travel. This is especially useful information if you already have springs on your vehicle and don't like the ride height or you need to over preload your springs to gain ride height.
For Example A Standard Spring: 1200.250.0500 (12" Free Length, 2.50" inside diameter, 500lb/in)
STEP 1: TRAVEL BEFORE COIL BIND
The example spring travel is 6.25" This number represents the total available travel from free height to coil bind.
STEP 2: TEST RANGE
Eibach calculates the first test point by taking 20% of 6.25" which equals 1.25"
Eibach calculates the second test point by taking 70% of 6.25" which equals 4.375"
The actual travel between these two points is 3.125" and this is where Eibach determines their spring rate.
4.375 - 1.250 = 3.125 inches
STEP 3: SPRING RATE TEST
Preloading the spring down 20% or 1.25" would equal a 500lbs force measurement.
Compressing the spring down 70% or 4.375" and the force measurement would equal 1565lbs.
3.125" of travel multiplied by 500 lb/in equals 1565 lbs of force.
3.125 x 500 = 1565
TOLERANCE:
With Eibach's precise spring rate tolerance of +/- 2% (500 x 2% = 10 lbs) the spring rate should fall between 490 and 510 lbs/in
