john hennessy wrote:
if you view it differently please explain, how would you compress a 100lb per inch spring by 3" without applying 300lbs to it.
The confusion seems to be in calling a 100lb/in spring that is compressed 3in, a '300lb' spring. While what was
trying to be explained may be true, the terminology was confusing as it goes against standard convention. For consistency of understanding, springs are almost always referred to exclusively by their spring rate and
not the amount of load they happen to be supporting at any given time. So saying a '300lb' spring indicates to most people a '300lb/in' spring. Interpreted that way the statement changes from the intended meaning and becomes incorrect. It further confuses the matter when the person doing the explaining uses the terms inconsistently, on one hand uses "300lb spring" to mean a 300lb load on a 100lb/in spring and on the other hand to mean the more conventional 300lb/in spring.
john hennessy wrote:
therefore if you have a 100lb. spring in your suspension and at ride hight it is compressed by 3" there must be 300lbs on that spring, you could remove it and replace it with a 300lb. spring that was 3" shorter and ride hight would remain the same
perhaps i did not make myself clear enough, if you have a 100lb. spring of a length X and compress it by 3", you know there is a load of 300lbs. on that spring
therefore, it could be replaced by a 300lb spring that was 3" shorter and there would be no deflection, the spring length would be X minus 3"
hoverver, if you added 100lbs. more to each spring, the 100lb spring would deflect another 1" because it is now supporting 400lbs, thats 1" for every 100lbs. applied but the 300lb spring would only deflect 0.333333333333", i could go on with the decimals but there would be no point, likewise my post.
This is a fairly common misconception about spring rates. If you replaced the 100lb/in spring compressed 3 inches with a 300lb/in spring 3 inches shorter, your ride height would
drop by 1 inch. This is because a 300lb/in spring with a 300lb load on it would also be compressed by 1 inch. As follows, a 300lb/in spring with a 400 lb load on it would compress by 1.333 inches, etc.