Coil spring info (way too much)

[87wildside]

If you have ever wanted to know what your spring rate is here is the formula to figure it out.

SW - to the fourth power
____________________
8CM - to the third power

No what does that mean you ask, I'll explain.
S= the torsional modules for steel which is 11,250,000
W= wire diameter
8 is a constant for all coil springs using this equation
C= number of "active" coils
M= mean diameter of the coil

Here is an example.
The 2000 S-10 (non ZQ8) uses a spring with a wire diameter or 0.625.
The overall diameter is 5.625. The mean diameter is 4.86 (simply subtract the width of the wire from the overall diameter to get the mean diameter)
Number of active coils is 5.75. (see pic at bottom)

Now with that info I'll show you how to do the equation.

11,250,000 X 0.765 X 0.765 X 0.765 X 0.765 which equals 3,852,993.4
That is the top of the equation.

8 X 5.75 X 4.86 X 4.86 X 4.86 which equals 5,280.4
That is your bottom number

3,852,993.4
__________
5,280.4

Or, 3,852,993.4 divided by 5,280.4 which equals 729

So the spring works out to be 729 lbs/in
If I was to cut a half coil off the spring rate would be raised to 799 lbs/in.

Example of "active" coils. Part of the text on the bottom right was cut off. It should read, Blue marks equal turns of the coil. Started from the bottom up in this example. The come out to 6 1/4.



If you need any help I'll try.

[87wildside]

MOOG coils spring part numbers and chart. I should mention the spring rate seems to be slightly off.
Pick up, sadly it only goes to 1996.
http://bbb-carb.com/coilsprings/Chev...S10-Pickup.htm
Blazer to 1997
http://bbb-carb.com/coilsprings/Chev...S10-Blazer.htm
Chart.
http://bbb-carb.com/moog_Coil_Springs.htm

[Hammer Head]

Wow.

[87wildside]

LOL, That's what happens when you go searching for spring rates and want to know what the stocker will end up at after being cut. Think I'll be happy with cut springs. My drop coils came to 550 or something, way to soft.

[BigTruckDrivah]

So if I would have just cut my coils instead of buying "drop" coils, I would bottom out less? Why didnt you tell us this earlier?! LOL. BTW, this should be a sticky.

[87wildside]

I just found the calculation again. Thought it was on the web but it was in a book so I posted it

Some after market coils have a higher spring rate for drop springs but with the rates the S10 has that seems doubtful. Maybe I should check the 2" springs in the shed..

[rentedmule]

That's great info! Do you have a rate estimate for the ZQ8 coils or do you need measurements?

[87wildside]

I need measurements and a pic just to make sure the are wound the same and if they are ground on the ends.

[12sws27]

Originally Posted by 87wildside

I need measurements and a pic just to make sure the are wound the same and if they are ground on the ends.

I already gave you all that. Remember?
http://www.s10planet.com/forum/showthread.php?t=19905

Now get to figuring!

[12sws27]

See?

Originally Posted by 12sws27

Ok back on track...
Stock coil, Non ZQ8 dimensions... Edit: I was just screwing with Eric, This is the measurement for ZQ8 springs.

Over all height.... 33.02cm
Wire diameter....18.5 mm
7 full coils.