7 Steps on How To Tune Rear Derailleur * flexco.com

Tuning a rear derailleur is a crucial skill for any cyclist, allowing you to optimize your bike’s performance and ensure smooth shifting. Whether you’re experiencing gear skipping, chain noise, or sluggish shifting, a well-tuned derailleur will restore your ride to its former glory. As the centerpiece of your bike’s drivetrain, the rear derailleur plays a vital role in transferring power from your legs to the rear wheel, allowing you to tackle different terrains with ease.

The process of tuning a rear derailleur may seem daunting initially, but it’s a relatively straightforward task that can be accomplished with the right tools and a methodical approach. By following a step-by-step guide, you can adjust the derailleur’s position, tension, and limit screws, ensuring that the chain engages with each gear smoothly and efficiently. A well-tuned derailleur will not only improve your riding experience but also prolong the life of your drivetrain components, saving you time and money on costly repairs in the long run.

To embark on this tuning journey, you’ll need a few essential tools, including a chain whip, a cable cutter, and a set of hex keys. A chain whip helps you safely remove the cassette, while the cable cutter allows you to trim excess cable housing. Hex keys, in various sizes, enable you to adjust the derailleur’s mounting bolts and limit screws precisely. With these tools at your disposal, you can delve into the steps involved in tuning your rear derailleur, empowering yourself with the knowledge of maintaining your bike’s drivetrain.

Calibrating the Shifting

5. Fine-tuning the Shifting Points:

After setting the limit screws, it’s crucial to refine the shifting points to ensure precise and effortless shifting. Here’s a detailed guide to fine-tuning:

Identify the Shift Points: Cycle through the gears using the right shifter. Notice the points where the chain jumps from one cog to another. These are your shift points.
Adjust the Barrel Adjuster: Locate the barrel adjuster on the rear derailleur. Turn it a small amount (less than a quarter turn) to adjust the shifting point. Turning the adjuster clockwise will move the shift point higher (to a larger cog), while turning it counterclockwise will move it lower (to a smaller cog).
Test and Refine: Cycle through the gears again, observing the shift points. Make further adjustments to the barrel adjuster as needed until the chain transitions smoothly and precisely at the desired points.

Remember, fine-tuning the shifting points is an iterative process that requires patience and precision. Take small incremental adjustments and test each change thoroughly before moving on.

Adjustment	Effect
Turn barrel adjuster clockwise	Move shift point higher (to larger cog)
Turn barrel adjuster counterclockwise	Move shift point lower (to smaller cog)

Checking the Cable Tension

To determine if the cable tension is correct, shift the rear derailleur to the smallest cog (the one closest to the wheel). If the chain is rubbing against the side of the cog, the cable is too loose. If the chain is skipping or jumping, the cable is too tight. Ideally, the chain should be taut but not so tight that it’s pulling on the derailleur cage.

To adjust the cable tension, you’ll need a cable tension gauge or a ruler:

Using a cable tension gauge: Attach the gauge to the spoke next to the derailleur cage, and pull on the cable until the gauge reads 10-15 Newtons (1-1.5 kilograms of force).
Using a ruler: Measure the distance between the derailleur cage and the outermost pulley. The ideal distance is 12-15 mm. If the distance is too great, the cable is too loose, and if the distance is too small, the cable is too tight.

Once you’ve adjusted the cable tension, shift through all the gears to make sure there is no rubbing or skipping. If necessary, fine-tune the tension until the shifting is smooth and precise.

Tips for Advanced Tuning

1. Check the Cable Tension

After making the initial adjustments, double-check the cable tension. If the cable is too loose, the derailleur may not shift smoothly or may jump gears. Conversely, if the cable is too tight, the derailleur may not shift at all. To check the cable tension, shift the chain into the smallest cog. If there is a slight amount of slack in the cable, it is properly tensioned.

2. Fine-Tune the Limit Screws

The limit screws prevent the derailleur from overshifting and damaging the chain or cassette. The high limit screw limits the derailleur’s movement to the smallest cog, while the low limit screw limits its movement to the largest cog. To fine-tune the limit screws, shift the chain into the smallest cog and adjust the high limit screw until the chain is aligned perfectly. Repeat this process for the low limit screw with the chain shifted into the largest cog.

3. Adjust the B-Tension Screw

The B-tension screw adjusts the distance between the derailleur’s upper pulley and the largest cog. This adjustment is crucial to prevent the chain from rubbing against the pulleys when in the largest cog. To adjust the B-tension screw, shift the chain into the largest cog and loosen the screw. Move the derailleur inward until the chain is just touching the pulley, then tighten the screw.

4. Check the Indexing

Indexing refers to the derailleur’s ability to shift smoothly and precisely between gears. To check the indexing, shift the chain up and down through the gears and observe if it shifts quickly and quietly. If the shifting is not smooth, you may need to fine-tune the limit screws or cable tension.

5. Lubricate the Derailleur

A well-lubricated derailleur will shift more smoothly and last longer. Apply a small amount of bike lube to the derailleur’s pivot points, pulleys, and cable.

6. Check the Chain for Wear

A worn chain can cause shifting problems. If you notice that your chain is skipping or slipping, it may need to be replaced.

7. Inspect the Cassette and Chainrings

Damaged or worn cassettes and chainrings can also cause shifting problems. Check the teeth for any signs of wear or damage.

8. Check the Rear Derailleur Hanger

The rear derailleur hanger is the part of the frame that the derailleur mounts to. If the hanger is bent or misaligned, it can affect the derailleur’s performance.

9. Troubleshooting Chart

Problem	Possible Cause	Solution
Chain skipping or slipping	Worn chain	Replace the chain
Derailleur not shifting smoothly	Cable tension too loose or too tight	Adjust the cable tension
Chain rubbing against the pulleys	B-tension screw not properly adjusted	Adjust the B-tension screw

10. Advanced Tuning Tips

For even more precise shifting, you can fine-tune your derailleur with the following tips:

Adjust the derailleur’s cage length to match the length of your chain.
Use a derailleur hanger alignment tool to ensure that the hanger is properly aligned.
Experiment with different cable routing methods to find the one that provides the best shifting performance.
Use a chain wear indicator to monitor the condition of your chain and replace it when necessary.
Keep your derailleur and cassette clean and well-lubricated for optimal performance.

How To Tune Rear Derailleur

A rear derailleur is a bicycle component that moves the chain across the rear cassette, allowing the rider to change gears. It is important to keep the derailleur properly tuned in order to ensure smooth and efficient shifting. Here are the steps on how to tune a rear derailleur:

Shift the chain to the smallest cog on the cassette.
Loosen the barrel adjuster on the derailleur cable.
Turn the B-screw counterclockwise until the upper pulley cage is approximately 4-5mm below the smallest cog.
Tighten the barrel adjuster until the chain can be shifted smoothly to the largest cog on the cassette.
Re-check the B-screw and make sure it is still set correctly.
Test the shifting by shifting through all the gears.

If you are still having problems with shifting, you may need to consult with a professional bike mechanic.

7 Steps on How To Tune Rear Derailleur