While rebuilding some Icon Vehicle Dynamics 2.0 FJ Cruiser rear shocks we took the opportunity to snap some pictures and explain more how they work.
Icon Vehicle Dynamics Digressive Shocks
Icon Vehicle Dynamics advertises that they use digressive pistons in their shocks for better chassis control (handling). But as you can see in our Piston Tech Article, there are some downsides to extremely digressive damping, and that digressive pistons don’t always mean digressive damping. So we dug into the IVD shocks to figure out what’s really going on.
IVD uses linear compression with large bleed and valve disks in a pyramid stack configuration. The result is a linear damping curve with good comfort on small bumps, and control on large ones.
Icon shocks use pistons designed to be digressive in rebound. However the rear FJ Cruiser shocks we opened up are using methods to make them act more linear. These methods include low digressive preload (probably 0.003″) and large bleed holes.
Icon Vehicle Dynamics improves the ride and control of their Digressive shocks by using linear compression, and marginally digressive rebound. By reducing the digressive nature of the shocks they are able to mitigate a lot of the downsides to digressive damping. The result is improved comfort on washboard and more control on big bumps (than a very digressive shock).