how to adjust back derailleur on mountain bike

How to Adjust a Back Derailleur on a Mountain Bike

Adjusting the back derailleur on your mountain bike is an essential skill for maintaining optimal shifting performance. Whether you're experiencing issues like skipping gears, difficulty shifting, or chain noise, a proper adjustment can make a significant difference. In this guide, we'll walk you through the steps to adjust your back derailleur effectively.

Tools You'll Need

Before you begin, gather the necessary tools a 5mm Allen wrench, a Phillips screwdriver, and possibly some bike grease. It’s helpful to have a bike stand or a way to secure your bike while you work.

Step 1 Inspect Your Derailleur

Start by checking the overall condition of your derailleur. Look for any signs of damage such as bent hangers or cracked components. Ensure that the derailleur pivots and springs operate smoothly. If any parts are damaged, consider replacing them before proceeding with adjustments.

Step 2 Set up the Gear Shifting

Shift your bike into the smallest gear (the highest gear) at the rear. This prepares the derailleur for adjustment. Next, locate the limit screws on your derailleur—usually marked as H (high) and L (low). The H screw limits how far the derailleur can move toward the wheel, while the L screw controls movement in the opposite direction.

With the bike in the highest gear, check if the derailleur aligns perfectly with the smallest sprocket. If it’s too far away or rubbing against the spokes, turn the H screw clockwise to bring it closer or counterclockwise to move it away. The goal is to ensure that the derailleur sits directly over the sprocket without making contact with the spokes.

Step 4 Adjust the Low Limit Screw

Next, shift into the largest gear (the lowest gear) at the rear. Repeat the alignment check by adjusting the L screw. If the derailleur isn’t aligned with the largest sprocket, adjust the screw until it aligns perfectly. Again, it should not make contact with the frame or derailleur when shifting into this gear.

Step 5 Fine-tune the Cable Tension

After setting the limit screws, shift through the gears to see how the bike performs. If you notice any hesitation or if the chain doesn’t shift smoothly, it could be due to insufficient cable tension. Locate the barrel adjuster on the derailleur or shifter and turn it to increase tension, which should improve shifting performance.

Step 6 Test the Shifts

Finally, take your bike for a test ride across all gears. Pay attention to how smoothly it shifts. Repeat adjustments as necessary until you achieve the desired performance.

Conclusion

Regular maintenance of your mountain bike’s back derailleur is crucial for a smooth and enjoyable ride. With these steps, you can ensure your bike shifts seamlessly, allowing you to focus on the trails ahead. Don't hesitate to seek professional help if you're uncomfortable with adjusting your derailleur yourself. Happy biking!