how to adjust rear derailleur on a mountain bike

How to Adjust the Rear Derailleur on a Mountain Bike

Adjusting the rear derailleur on a mountain bike is an essential skill for any cyclist. Proper adjustment ensures smooth shifting, which can significantly enhance your riding experience. Whether you're experiencing skipping gears, misalignment, or just want to maintain your bike, understanding how to adjust your rear derailleur is crucial.

Tools You’ll Need

Before you start, gather the necessary tools - A Phillips screwdriver - A 5mm Allen key - A bike stand (optional but recommended) - Cleaning cloth - Lubricant (if required)

Step 1 Inspect the Derailleur

Begin your adjustment by inspecting the rear derailleur for any visible damage or excessive dirt. Ensure that the derailleur hanger, which connects the derailleur to the bike frame, is not bent. If it is, you may need to realign or replace it. Clean any dirt or grime surrounding the derailleur to ensure a smooth operation.

Step 2 Check the Cable Tension

Pull gently on the derailleur cable to check its tension. If the cable is too loose, shifts may be sluggish. Conversely, if it’s too tight, it may cause the bike to shift unexpectedly. To adjust the cable tension - Locate the barrel adjuster on the derailleur or shifter. - Turn the barrel adjuster clockwise to increase tension or counterclockwise to decrease it. - Test the shifting after each adjustment to find the right balance.

Step 3 Adjust the Limit Screws

The limit screws on the rear derailleur control the range of motion of the derailleur. These screws prevent the chain from derailing off the cassette or chainrings. There are two limit screws, often marked as H (high) and L (low) - High Limit Screw This controls how far the derailleur can push the chain towards the smallest cog. Adjust this screw so that when you shift into the smallest gear, the derailleur aligns perfectly with the cog. - Low Limit Screw This screw controls the movement towards the largest cog. Similar to the high limit, adjust it so that when you’re in the largest gear, the derailleur doesn't push the chain off the cassette.

Step 4 Fine-tune the B-Tension Screw

The B-tension screw adjusts the distance between the derailleur and the largest cog. This distance is crucial for smooth shifting, especially under load. To adjust - Shift to the largest cog on the cassette. - Loosen the B-tension screw slightly and pull the derailleur away from the cog until there’s a small gap, usually around 5-6mm. - Tighten the screw and test the shifting.

Step 5 Test the Shifting

After making these adjustments, it's time to test the bike. Shift through all the gears, from the smallest to the largest cog and back. Listen for any skipping or grinding sounds, which may indicate that further adjustments are necessary.

Step 6 Regular Maintenance

Regular maintenance is key to ensuring your rear derailleur continues to function well. Inspect and clean the drivetrain components regularly, and lubricate the chain as needed.

Conclusion

Adjusting the rear derailleur on your mountain bike doesn't have to be daunting. With some basic tools and a bit of patience, you can achieve smoother shifting and a more enjoyable ride. Regularly check your setup to keep your bike in peak performance and enjoy your time on the trails!