EzK

Are the Rock Krawler 2.5" springs progressive in that they provide multiple spring rates for comfort and ride or do they just have a light rate to extend the spring and keep it in place when flexing?

"The Stock Mod system features a progressive rate front coil to allow the same great travel our 3.5" systems offer at a 2.5" lift height." -RK

What about AEV?

Any actual stats on either spring or are they trade secrets?

JKPier

I thought progressive meant as spring is compressed, it gets stiffer (variable resistance). So at normal load it fives easily butnunder higher load its stiffens up to prevent bottoming. I do not think it means its tunable or adjustable.

JohnnyQuik

How I understand it: Progressive coils mean that the top part of the springs have a softer rate than the bottom part. As the spring compresses the top coils take the initial load making for a softer initial spring rate. As the coil compresses further the overall spring rate increases and becomes stiffer as the bottom coils start to compress. This allows the spring to become progressively more stiff as it's compressed. Perfect right? So why aren't they used everywhere? Because the initial spring rate is soft, the vehicle tends to float and wander more than if it had constant rate springs with the same average spring rate.