I need help determing what springs would be stiffer. I have coil spring with 8 coil turns and it's got 11mm coil wire diameter. If I make a new coil with 12 coil turns and stick with the same coil wire diameter (11mm), shouldn't I get stiffer spring or do I need to make it from larger wire diameter??? HELP!!!

more coils = longer spring = softer rate

less coils or thicker wire = stiffer rate, all else equel

think of it this way, more coil turns means more places that the weight can compress the spring, therefore, easier to compress. try bending a 4 inch piece of 25" rod - pretty hard. Now try bending a 6 foot piece - pretty easy. same concept.

K = (Gd^4) / (8nD^3)

in other words


coil spring rate = ( material rigidity x wire diameter ^4 ) / ( 8 x number of coil wraps x coil diameter ^ 3 )

For a given material (G) you can see increasing wire diameter increases spring rate, and increasing mean diameter of the coil, or the number of coil wraps, decreases rate.

You're making your own coils? Cool. How? :confused: Or do you work at a spring shop...?

There are few spring shops in my place and they said I can get spring whatever I like. Now I am considering few options how to do it. I was using rear coils from 4 doors Sidekick on both ends, but zuk is rolling too much when cornering but the articulation is awesome. Now I want to make a spring to be somewhere in the middle of articulation and handling