The Ins & Outs Of Damper Technology
The basic theory behind shocks is that they absorb and dissipate the energy and shock between the road or trail and the vehicle. The cylindrical contraptions have a telescoping rod on one end that's fitted with valves; the other end is immovable and affixed to the frame or axle of the vehicle. There are two basic mechanical movements of a shock absorber. When a vehicle drives over a bump, the shock compresses, pushing the piston into the shock. This is called compression. When the vehicle clears the bump, the shock decompresses. This is called rebound. Shock cylinders are filled with either hydraulic fluid, gas, or air. As the vehicle travels down the road, the wheel moves up and down with the contour of the road. This creates energy, which is absorbed by the action of the valve as it passes through the oil or gas in the damper.
Shock absorber theory may seem basic, but the mechanics, physics, and science that go into them can be mind-boggling. The dampers smooth the ride by working in conjunction with the springs. It's important when building a vehicle that the two components be properly matched and complement each other. If you have just spent money on a set of custom leaf springs, then don't buy the cheapest hydraulic 50/50-valved shock you can find. Some of the low-end shocks aren't valved vehicle-specific. This means a company that sells a shock for a fullsize Ford truck is selling a shock for a midsize Toyota truck with the same valving. What does this mean for you? Poor or limited on- and off-highway performance.
When it comes to choosing high-quality shock absorbers, the selections are nearly limitless. The key to choosing the right shock is doing your research and knowing exactly how it will perform on the highway and out on the trail. Your choices are hydraulic shocks, mono- or multitube shocks, coilovers, bypass shocks, and gas and air shocks.