Shock absorbers control unwanted motion through a process commonly called dampening (hence, their alias "dampeners"). They turn the kinetic energy of suspension movement into heat energy, which is then dissipated through the shock body. Without shocks, your rig's springs would bounce up and down after hitting a bump (taking your rig with them) until all of the energy put into the springs by the bump was used up. So a shock's job sounds simple, right?

Well, here's the thing. While fine for street use, a standard monotube or twin-tube shock has drawbacks. The biggest disadvantage is that when asked to endure sustained rough terrain, they can overheat. This is called aeration, and it's what takes place when the oil in the shock foams due to the heat generated by the shock, turning the previously mentioned kinetic energy of suspension movement into heat energy. The result is that the shock loses its ability to dampen. This allows that crazy spring motion to run unabated. This not only creates a bouncy ride but also scary handling.

Remote-reservoir shocks can help solve this problem. They're designed with an external reservoir that increases fluid capacity. This increase in capacity helps lower fluid temperature, thus offering the ability to blast over rough terrain without experiencing shock fade due to overheating.