how to adjust rear shock

3 min read 06-02-2025

Whether you're a seasoned mountain biker or just starting out, properly adjusting your rear shock is crucial for a comfortable and controlled ride. A poorly adjusted shock can lead to a harsh, uncomfortable experience, or a wallowy, uncontrolled feel. This guide will walk you through the process, covering different types of shocks and adjustments.

Understanding Your Rear Shock

Before diving into adjustments, it's important to understand the basic components and functions of your rear shock. Most modern shocks offer adjustments for rebound, compression, and air pressure (for air shocks). Some higher-end shocks offer even more nuanced settings.

Types of Rear Shocks

Coil Shocks: These use a spring for suspension. Adjustments are typically limited to rebound.
Air Shocks: These use pressurized air for suspension. They offer the most adjustability, allowing you to fine-tune your ride for different terrains and riding styles. Air pressure is a key setting here.

Diagram of a rear bicycle shock with labels for rebound and compression adjustments

Setting Your Sag

Sag is the amount your shock compresses under your weight when you're sitting on the bike. Proper sag is the foundation of good shock adjustment. Too little sag results in a harsh ride, while too much leads to a wallowy feel.

How to Set Sag

Find your shock's recommended sag percentage. This is usually printed on the shock itself or found in the manufacturer's specifications. Common percentages range from 20-30%.
Measure your shock's total length. Use a ruler or measuring tape.
Calculate your desired sag. Multiply your shock's total length by the recommended sag percentage (e.g., 25% sag on a 200mm shock is 50mm).
Sit on your bike in your typical riding position. Have a friend measure the distance between the top of your shock and the frame.
Adjust your air pressure (for air shocks) or preload (for coil shocks) to achieve the desired sag. Add or remove air or adjust the preload until the measurement matches your calculated sag.

Adjusting Rebound

Rebound controls how quickly your shock extends after being compressed. Too slow rebound leads to a sluggish, uncontrolled feel, while too fast can cause the bike to become bouncy and unstable.

How to Adjust Rebound

Find the rebound adjustment knob. It's usually a dial or knob near the bottom of the shock.
Start with the rebound fully closed.
Slowly open the rebound, one click at a time. Test the shock after each click by compressing it and observing how quickly it returns to its original position.
Find the sweet spot. You want the shock to return smoothly and quickly, without bouncing excessively.

Adjusting Compression

Compression controls how quickly your shock compresses. This setting affects how your bike handles impacts and how much it squats under pedaling forces. Many shocks offer both high-speed and low-speed compression adjustment.

How to Adjust Compression (Low-Speed)

Locate the low-speed compression adjustment. This is often a separate dial from the rebound adjuster.
Experiment with different settings. Start with the compression relatively slow, then gradually increase it until you find a setting that balances comfort and control.
Consider your riding style and terrain. For rough terrain, you may prefer a slower compression, while for smoother trails a faster setting may be better.

Adjusting Compression (High-Speed)

High-speed compression controls how the shock reacts to large impacts. It’s typically found on higher-end shocks and is less frequently adjusted than low-speed.

Fine-tuning Your Setup

The best settings will depend on your weight, riding style, and terrain. Experiment with different combinations of air pressure, rebound, and compression settings to find what feels best for you. Consider logging your settings so you can easily revert to a known good setup.

Remember, adjusting your rear shock is an iterative process. Don't be afraid to experiment, and don't be discouraged if it takes some time to find the perfect settings. A properly adjusted rear shock can dramatically improve your riding experience.

Further Resources

For more in-depth information, consult your shock's manual and the manufacturer's website. Many brands offer videos and online guides that can provide additional support.