what spring rate are these?

[Robo86]

hey guys,

how can i tell what the spring rate is of these?
help me out

thanks robo

[70XIN]

robo, you can't tell the spring rate by number of coils alone. thickness of coils, space between etc etc come into it

a suspension shop will be able to tell you, and at worse a new set of springs are 100-150 a pair

[RobertoX]

1kg/mm


i need wire diameter, number of active coils, free height etc

by eye is about 7-8kg

but eye is not accurate

[SpotterOne]

Are there any markings on the spring? My Eibach springs have a number painted onto them signifying the technical data relating to the spring.

[kaibeecee]

some brands of spring are colour coded for a certain weight range.

go to a decent suspension shop that does spring compression, and they should* be able to pressure test them for a more accurate reading.

*note: some shops will look at you cock-eyed and just tell you to get bent.

[rthy]

robo why dont you take them out and measure them yourself? do you know how to do that?

[ae71]

I don't how do you Sam?

[Robo86]

there not mine... just wondering cause im thinking of buying them, and the acution listing doesnt say anything about rates..

thanks anyway

[ghetto ke]

and Inner Diameter... Free height is not so important. The formula goes a little something like this:

G = 1010.6 kg/mm - (Modulas of Elasticity) Property of Spring Steel which is Constant, this is an approximate value but will get you within 10%

Nc = No of Active Coils (As these are Squared and Ground -1 from Total No of Coils)

Wd = Wire Diameter of Spring

Di = Inner Diameter of spring

_____G . Wd_____= Spring Rate (kg/mm)
Nc . ((Wd+Di)/Wd)³

for example: It looks like those springs are about 8.5 Coils, 12mm Wire Diameter and 2.5in Internal Diameter = 65mm.


Wd = 12mm
Di = 65mm
Nc = 7.5 (Total No Coils is 8.5 -1)

would result in a Spring Rate of about a 6kg/mm

[ghetto ke]

Also If you have a spring Rate in kg/mm and want to convert it to the old lb/in multiply it by 56

i.e. 8kg/mm x 56 = 448lb/in