Spring rate testing

Ryan Storzbach · **Posted:** Wed May 07, 2008 5:40 pm

Anyone know where I could take some springs from a set of coilovers to get the rate measured? Does Mark at Hubcap Heaven do this sort of thing?

Wes Eargle · **Joined:** Mon Oct 27, 2003 9:47 am **Posts:** 3683

Progressive or linear?

Ryan Storzbach · **Posted:** Wed May 07, 2008 7:20 pm

Linear

DickRasmussen · **Posted:** Wed May 07, 2008 8:13 pm

For accurate (versus ball park) you might try these guys: http://www.apexvintage.com/home (formerly Krause & England).

For ball park, if the springs aren't too stiff you might be able to do it with known weights and a tape measure, etc.

For ball park, the springs might actually be marked.

Also for ball park, if the motion ratio is VERY close to 1 and you know the approximate corner weights of the car simply measure the spring deflection in the car under load.

Ryan Storzbach · **Posted:** Wed May 07, 2008 9:55 pm

^^ thanks!

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

You can also calculate it and come close:

k = (G*d^4)/(8*n*D^3)

k = constant, pounds of load per inch of deflection

G = modulus of rigidity of spring material, pounds per square inch

d = wire diameter, inches

n = number of active coils, which is the number of coils subjected to flexure (always less than the total number of coils)

D = mean coil diameter, inches = Outer Diameter - Wire Diameter

G is about 29x10^6 for typical spring steel

From http://www.engineersedge.com/spring_tension_calc_k.htm

THSCC Forums

Spring rate testing

Who is online