This resistance causes a deadening effect, which in turn kills spring oscillation. This is how a traditional shock absorber works. MacPherson struts operate in a similar manner, except that the shock, or strut, has been placed inside a coil spring. As we've touched on earlier, this reduces space and makes for a very effective coupling between shock and spring. Gas-filled shocks work like regular shock absorbers, except that the air inside the chamber has been replaced by a pressurized gas.
Aeration causes the shock to lag.
Air shocks have a separate, sealed air chamber inside the shock absorber. Because this chamber is sealed, it is not subject to aeration. This produces an even better ride than gas shocks. Here's how it works. The air chamber has a valve coming off it, just like a bicycle tire.