Compression damping controls how quickly your fork or shock moves through its travel when it absorbs an impact. Decreasing the amount of compression damping (turning the knob anti-clockwise or towards the - sign) allows more oil to flow, making the shock feel softer, giving you more control over harsh sections of trail. Increasing the amount of compression damping (turning the knob clockwise or towards the + sign) impedes the flow of oil and makes the suspension feel firmer and more supportive.
Rebound damping controls how quickly your suspension extends back to its original position after absorbing an impact. If it rebounds too quickly, it may feel like a pogo stick, resulting in less control. You can increase the amount of rebound damping by turning the knob clockwise or towards the + sign. This impedes the flow of oil and slows down rate of return. On the flip side, if your suspension feels sluggish or doesn’t recover fully between quick hits, you can decrease the amount of rebound damping by turning the knob anti-clockwise or towards the - sign. This increases the flow of oil and allows your suspension to recover faster.
Many full suspension Trek mountain bikes come with adjustable leverage rate that can be tweaked with a simple flip of a chip. When running in the less progressive setting, your suspension will feel softer through rocks, roots and square-edged bumps. In the more progressive setting, you’ll find more bottom-out resistance, pedalling efficiency and gain the ability to run a coil shock.