If the wire diam is the same and there are less winds then they will be stiffer springs.
The more winds you have (given the same length) then the length of wire used is longer, hence it is "softer". It is the same principle of cutting a section of spring off to stiffen it.
You can think of it as a spring is simply a convenient way to bend a metal rod. The more winds you want the longer the rod has to be to make a spring of the same length. If you gripped a rod at both ends with your thumbs pointing to each other, to bend it you want to raise both your thumbs up. It is much easier to do that the longer the rod is. Progressive springs have tight winds at one end so as the spring compresses these collapse onto each other which locks off those winds effectively shortening the rod. This is the same as starting with your hands wide and then moving them closer together on the rod, it will become harder to bend.
Shame to contradict on my first post, but the stiffness of a round cross section torsion bar (spring is a coiled torsion bar) is proportional to the fourth power of the torsion bar diameter. As a result a slight increase in diameter results in a large increase in stiffness.
Quote from: stet on 11 May 2017, 06:55:19 pmShame to contradict on my first post, but the stiffness of a round cross section torsion bar (spring is a coiled torsion bar) is proportional to the fourth power of the torsion bar diameter. As a result a slight increase in diameter results in a large increase in stiffness....That would make the thou spring about 17% stiffer if all other variables are the same. And even if you do measure the spring rates it probably doesn't help much since the springs are different lengths and the FZ6 one looks as if it'll hit the stiffer rate a bit sooner.