Understanding the Rear Derailleur
The rear derailleur is a crucial component of your bike’s drivetrain. It moves the chain from one cog to another, allowing you to change gears. Correct adjustment ensures smooth and accurate shifting.
Essential Tools
- 5mm Allen wrench
- Phillips screwdriver
- Bike stand (optional)
- Small brush or cloth
Having the right tools will make the adjustment process much easier. A bike stand is useful but not essential.
Inspect the Rear Derailleur
Check for any obvious signs of damage or wear. Look at the derailleur hanger to ensure it isn’t bent. A bent hanger can cause shifting issues and should be straightened or replaced.
Clean the derailleur with a small brush or cloth to remove any dirt and grime. A clean derailleur operates more smoothly and that makes adjustments easier.
Adjust the Limit Screws
Locate the two limit screws on the derailleur. These screws are usually marked as ‘H’ (high) and ‘L’ (low). The high limit screw controls how far the derailleur can move towards the smallest cog. The low limit screw controls the movement towards the largest cog.
Shift the derailleur to the smallest cog. Turn the H screw to align the jockey wheel directly under the smallest cog. This prevents the chain from shifting past the smallest cog and into the frame.
Next, shift the derailleur to the largest cog. Adjust the L screw to align the jockey wheel under the largest cog. This prevents the chain from falling into the wheel.
Adjust the Cable Tension
Shift the chain to the middle cog. Change the gears using the shifter. If the chain struggles to move to a larger cog, increase the cable tension. Turn the barrel adjuster counterclockwise in small increments.
If the chain struggles to move to a smaller cog, decrease the cable tension. Turn the barrel adjuster clockwise. Test the shifting again and make further adjustments as needed.
Fine-Tuning the Derailleur
Shift through all the gears to check for smooth and accurate shifting. Make small adjustments to the barrel adjuster as needed. If the chain doesn’t shift smoothly, revisit the limit screws and cable tension.
Check the B screw on the derailleur. This screw controls the distance between the jockey wheel and the cogs. Adjust the B screw to maintain a consistent distance. This ensures efficient shifting between gears.
Check for Common Issues
Listen for any unusual noises when shifting. Clicking or grinding sounds indicate misalignment or incorrect tension. Recheck the limit screws and cable tension if you hear these noises.
Ensure the chain is in good condition. A worn-out chain can cause poor shifting performance. Replace the chain if it shows signs of wear.
Test Ride
Take your bike for a test ride to ensure the adjustments hold up under real riding conditions. Shift through all the gears while pedaling to check for any issues. Make further adjustments if necessary.
Maintenance Tips
Regularly clean and lubricate the derailleur and chain. This can prevent dirt buildup and prolong the life of your components.
Periodically check the cable tension and adjust as needed. Over time, cables can stretch and affect shifting performance.
Inspect the derailleur hanger for any signs of bending or damage after any crashes or rough rides.