QUOTE (brando)
another option is to use spring clamps.
spring clamps effectively remove a coil from the active list.
cutting a coil effectively removes a coil from the active list.
How are they different, effectively?
QUOTE (brando @ Mar 22 2011, 06:44 AM) <{POST_SNAPBACK}>
the only way you can stiffen a coil is by adding wire thinkness. if you look at an aftermarket spring vs. a factory spring in most cases you will find many more coils than the stock one and in some cases it will either be the same length or taller.
you realize that that's a non-sequitor, right?
adding wire thickness has nothing to do with more coils or taller springs.
QUOTE (brando)
when a spring is weighted at say 100 lbs. and has 4 coils that means that every coil it has is rated at 25lbs. when you take out 1 coil it drops it to a 75# spring.
....and this is Load Rating, which is related to, but not the same as, Spring Rate.
BTW your 'only' statement flies in the face of the prevailing theory. the PT says removing active coils, thickening the wire (your 'only' option), or making the coil diameter smaller (mostly impractical to this application) INCREASES the rate. Adding coils, thinning the wire, or fattening the coil diameter (still impractical, mostly) DECREASES the rate.
the math that everyone uses for coil spring rates look something like this:
SR = (MoSS x WD^4) / (8 x AC x CD^3)
where SR = Spring Rate of Coil Spring - pounds per square inch
MoSS = Modulus of Spring Steel (generalized as 11,250,000 lb / in^2)
WD = Wire Diameter - inches
AC = Active Coils
CD = Mean Coil Diameter - inches
source - one of many
everyone who is interested in the topic says that wire length is important, since the coil spring functions as a wound torsion spring, and torsions care about their length.
however, you'll notice that the formula above (and most of the other versions of it) can not distinguish between two 10 coil springs of the same outer diameter made from the same wire; one with 1 inch gaps between adjoining coils, and one with 10 inch gaps between adjoining coils.
we can all agree that those two springs would differ greatly in their amounts of wire....and their rates should be wildly different as well, but the math says they will be the same.
so, here's a question for our new metallurgist and race suspension extraordinaire:
is there a more accurate method of calculating spring rates? (or one that agrees with your 'only' position?)
once I know where you stand on the accepted math, we can continue this discussion.
(and so you know, i don't entirely disagree with some of your concepts)
Edited by psychoboy, 22 March 2011 - 03:10 PM.