Adustment knobs are the driver's direct input to the coilovers, in regard to damping force, tuning suspension for driving style and/or to improve vehicle characteristics for a particular track or driving environment. Adjustment knobs are used to adjust the speed at which the damper piston(s) compress and rebound, e.g., softer damping allows the piston to compress quicker and rebound quicker, while stiffer damping causes the piston to compress slower and rebound slower. There are many reasons a driver would want control over damping with the turn of a knob but a few of the most common reasons are; to improve ride quality for daily commuting with the vehicle while still having the option to tune suspension more aggressively for a track or auto cross day; to dial in, dial out, or to neutralize understeer and oversteer. Understeer and oversteer of the vehicle should be adjusted for different tracks, tire wear/life, and weather by either stiffening or softening the compression and rebound via the adjustment knobs on the front, rear, or both front and rear of the vehicle. No matter how you use your vehicle, BC Racing Coilovers give you the ability to adjust damping force with the turn of a knob.