[no subject]

c = G*pi*d^4/(57.3*32*l)
Where c= spring rate
d = bar diameter
l = bar length
G= modulus of elasticity (78.5kN/mm^2 for hot formed springs, 81.4kN/mm^2 cold)
all dim in mm...

This is NOT correct for hollow bars, I'd have to find a desing book for that...

Helical springs (refresher for the digest):

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

where
d = "bar" diameter
D = coil diameter
n = number of turns in the coil spring
G = modulus (same as above)
again all in metric units, c = N/mm

And I recall a comment that if you cut a spring, then the car might raise-
this is NOT true.  Yes, the spring rate increases linearly with the number
of coils lost, but the rest height goes down the same amount...

Hope this helps
Eric Storhok

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