I can't seem to find this answer anywhere... and there's no suspension tech forum here...

Progressive springs means that the RATE CHANGES as it compresses. That means it's inadequate to give a single rate on a non-linear spring. So when a rate is listed for a spring, what does this represent? (average, max, min, etc?)

 

Good one... I don't know what's listed, but you're right. In order to really know the answer, you'd have to get a curve of springrate vs. compression, or a curve of force vs. displacement for the entire range of motion.

It's a lot like publishing peak values for torque & hp. They don't tell you what the REST of the curve looks like.

 

it means for each additional inch of spring compression, it takes more weight to compress it the same amt.

so:

lets say 500 lbs makes the spring compress 1"
well to make it compress 2", it will take more than 500 additional lbs... so maybe 1250 it will compress 2"
to get the third inch down, lets say it takes 1000 more lbs... so now a total of 2250 lbs to compress the spring 3"

if it werent progressive, every 500 lbs would mean 1 more inch of compression.

hope that makes sense for ya.