In our multi-rate springs each coil is spaced differently making them a variable spring rate. Initially it is easy to compress these springs for the first couple of inches. As you apply more force, the coils come closer to each other. After a certain point, the coils at the bottom 1/4 of these springs begin to touch each other and finally become inactive or dead, which makes the spring stiffer. The more force you apply to our multi-rate spring the more the rate increases. So, these springs are compliant to very small bumps on the road, while achieving control when needed off road, hard braking, and turning. These springs allow you to achieve the highest performance while driving hard and providing a smooth, comfortable drive the rest of the time. For 2010 trucks, we have found that using a Linear rate coil works best with the heavier 4th Generation vehicles, giving a very supple and smooth ride while still keeping performance to the absolute maximum.