When it comes to mountain biking, suspension setup is crucial for optimal performance and comfort. One of the key aspects of suspension setup is ensuring the correct amount of SAG in your fork. SAG refers to how much your suspension compresses under your weight when you are seated or standing on the bike. While some SAG is necessary for effective suspension, having too much can lead to a host of issues. In this post, we’ll explore what happens if your MTB fork SAG is too big and how to address it.

Reduced Efficiency

Climbing Performance: When climbing, especially on steep or technical trails, too much SAG can cause the front end of your bike to dive excessively. This dive can lead to poor traction and control, making it harder to maintain your line and momentum.

Handling Issues can be cause by too much MTB fork SAG

Steering Precision: The geometry of your bike is carefully designed for balance and control. Too much SAG alters this geometry, often resulting in sluggish and imprecise steering. This change can make navigating tight trails or technical sections more challenging and less enjoyable.

Cornering: When cornering, a fork with excessive SAG can dive too much, compromising traction and stability. This issue can lead to understeer or oversteer, making it harder to carve through turns with confidence.

Suspension Performance

Bottoming Out: One of the most immediate impacts of excessive SAG is the increased likelihood of bottoming out your suspension. With less travel available to absorb impacts, you’ll hit the limits of your suspension more frequently on rough terrain or big hits, leading to jarring and potentially damaging impacts. But be aware, while bottoming out sometimes is ok, especially on hard hits, to always bottoming out is bad.

Increased Wear and Tear

Component Wear: When your fork is constantly working in an over-compressed state, it places undue stress on the suspension components. Over time, this can accelerate wear and potentially lead to premature failure of parts such as seals, bushings, and the suspension internals. And as you know, mountain bike parts are expensive and this can be very bad for your wallet ;-).

Tire Wear: Poor suspension setup can lead to uneven tire wear. If the front tire is diving too much, it may scrub against the terrain more aggressively, leading to faster wear and potentially affecting grip.

Large MTB fork SAG and Rider Fatigue

Comfort: A bike with too much fork SAG can feel uncomfortable, especially over long distances. A harsh suspension can be tough on your joints as well as your back.

How to Correct Excessive SAG

1. Adjust Air Pressure: For air-sprung forks, increasing the air pressure can help reduce SAG. Consult your fork’s manual for the recommended pressure settings based on your weight and riding style.
2. Adjust Preload: If you have a coil-sprung fork, increasing the preload can help reduce SAG. This adjustment is usually made by turning a dial or adjusting a spacer on the fork.
3. Check for Leaks: Ensure there are no air leaks in an air-sprung fork, as even small leaks can lead to increased sag over time. Regular maintenance and inspection can help prevent this issue.
4. Increase Spring rate: A higher spring rate or coil force on your suspension should lead to less SAG. There are many spring rate calculators out there, who can help you to find the right spring rate.
5. Set Up Correctly: Follow the manufacturer’s guidelines for setting up your fork. This setup typically includes setting the SAG to a percentage of the total travel (usually 20-30%) while you are in your normal riding position.

Conclusion

Proper suspension setup, including correct MTB fork SAG, is essential for getting the best performance and enjoyment out of your mountain bike. If you’re experiencing any of the issues mentioned above, take the time to check and adjust your fork SAG. By doing so, you’ll improve your bike’s efficiency, handling, and overall ride quality, making your mountain biking adventures more fun and rewarding. Happy riding!

In case you need help with your SAG and other mountain bike settings, download SAGLY. SAGLY is a complete mobile guide for your mountain bike settings and maintenance.