If you find yourself pedaling but not going anywhere while riding your bike, your gears may need to be calibrated. The culprit may be a poorly tensioned or misaligned derailleur, which has a complex setup with two sets of stops and tension limits with adjustment screws for both high and low ends. Calibrating a derailleur will require precise adjustments, and it’s essential to go through the process patiently to get satisfactory results.
First, you need to know the different parts of a derailleur and their functions. The derailleur cage is the part that moves back and forth to shift the chain between gears. The derailleur pulley wheels guide the chain as it moves through the gears. The derailleur hanger is the part that attaches the derailleur to the bike frame. The derailleur cable is the part that connects the shifter to the derailleur and moves the derailleur cage back and forth. To calibrate a derailleur, you will need to adjust the cable tension, the high and low limit screws, and the derailleur hanger alignment.
Once you have identified the parts of the derailleur, you can begin calibrating it. First, shift the derailleur into its highest gear. Then adjust the barrel adjuster on the derailleur cable until there is just enough tension to prevent the chain from skipping. Next, shift the derailleur into its lowest gear and adjust the limit screws so the derailleur cage is directly below the smallest cog. Finally, check the derailleur hanger alignment by shifting the derailleur back and forth through all the gears. The derailleur cage should move smoothly and without any binding or rubbing. If the derailleur cage is not moving smoothly, you may need to adjust the derailleur hanger alignment.
Understanding Shifting Systems
In order to properly calibrate a Shimano derailleur, it is important to have a basic understanding of how shifting systems work. A derailleur is a mechanical device that moves the chain from one sprocket to another on a bicycle. When you shift gears, you are essentially changing the distance between the chain and the sprockets, which in turn changes the gear ratio. This allows you to adjust the amount of effort required to pedal the bike and maintain a comfortable cadence.
There are two main types of shifting systems: indexed and friction. Indexed shifting systems use a set of detents to hold the derailleur in specific positions, which correspond to each gear. Friction shifting systems rely on the tension of the cable to hold the derailleur in place. While friction shifting systems are generally less precise than indexed shifting systems, they are also more durable and easier to adjust.
The following table summarizes the key differences between indexed and friction shifting systems:
| Feature | Indexed Shifting | Friction Shifting |
|—|—|—|
| Precision | High | Low |
| Durability | Low | High |
| Ease of adjustment | Difficult | Easy |
Tools and Preparation
Tools
To successfully caliber a Shimano derailleur, you will require the following tools:
- Allen wrench set
- Phillips head screwdriver
- Chain lube
- Ruler or measuring tape
- Torque wrench (optional)
Preparation
Before starting the calibration process, ensure that your bike is clean and the drivetrain is free of dirt and debris. Apply a light coat of chain lube to all moving parts of the derailleur and chain to reduce friction and improve shifting performance.
Next, place the bike on a stable work stand or elevate the rear wheel so that the tires are off the ground. This will allow you to easily access the derailleur and make adjustments smoothly.
To prevent any damage, avoid overtightening screws and bolts while performing the calibration. Use a torque wrench if available, or tighten the screws just enough to secure them without applying excessive force.
Finally, check the chain tension to ensure it is neither too loose nor too tight. An optimal chain should have a slight amount of slack, allowing for proper shifting and minimizing wear on the drivetrain components.
Adjusting Limit Screws
Limit screws control the derailleur’s maximum travel in both directions, ensuring that the chain doesn’t fall off the sprockets or rub against the spokes. There are two limit screws: the high limit screw limits the derailleur’s movement toward the larger sprockets, while the low limit screw limits its movement toward the smaller sprockets.
High Limit Screw Adjustment
To adjust the high limit screw, shift the rear derailleur to the largest sprocket. While holding the derailleur body in place, turn the high limit screw clockwise until the chain just touches the outer edge of the sprocket. Then, turn the screw counterclockwise 1/4 to 1/2 turn to create a little slack in the chain.
Low Limit Screw Adjustment
To adjust the low limit screw, shift the rear derailleur to the smallest sprocket. While holding the derailleur body in place, turn the low limit screw counterclockwise until the chain just touches the inner edge of the sprocket. Then, turn the screw clockwise 1/4 to 1/2 turn to create a little slack in the chain.
Troubleshooting Limit Screw Adjustments
If the chain is falling off the sprockets, the limit screws may need to be tightened. If the chain is rubbing against the spokes, the limit screws may need to be loosened. It’s important to make small adjustments to the limit screws and test the shifting before making further adjustments.
| High Limit Screw | Low Limit Screw | |
|---|---|---|
| Purpose | Limits derailleur movement toward larger sprockets | Limits derailleur movement toward smaller sprockets |
| Adjustment | Turn clockwise to tighten, counterclockwise to loosen | Turn counterclockwise to tighten, clockwise to loosen |
| Troubleshooting | Chain falling off sprockets may indicate need to tighten | Chain rubbing against spokes may indicate need to loosen |
Indexing the Derailleurs
Indexing the derailleurs is the process of aligning the derailleur pulleys with the sprockets on the cassette or freewheel. This ensures that the chain moves smoothly and efficiently between gears. To index the derailleurs, you will need a chain whip, a hex wrench, and a screwdriver.
Rear Derailleur Indexing
1. Shift the rear derailleur to the smallest sprocket on the cassette (the one closest to the wheel).
2. Use the chain whip to hold the chain taut.
3. Use the hex wrench to loosen the barrel adjuster on the rear derailleur.
4. Turn the barrel adjuster until the chain is aligned with the center of the smallest sprocket. To do this, look at the derailleur pulley directly above the smallest sprocket. The chain should be running in the middle of the pulley.
5. Tighten the barrel adjuster.
6. Shift the rear derailleur to the largest sprocket on the cassette (the one furthest from the wheel).
7. Repeat steps 3-5 to align the chain with the center of the largest sprocket.
8. Shift the rear derailleur through all the gears to check the indexing. The chain should move smoothly and efficiently between gears. If the chain is not shifting properly, you may need to make further adjustments to the barrel adjuster.
| Tools – | Uses – |
|---|---|
| Chain Whip | Holds the chain taut |
| Hex Wrench | Loosens and tightens the barrel adjuster |
| Screwdriver | Adjusts the cable tension |
Fine-tuning the Barrel Adjusters
Once the initial setup is complete, you can fine-tune the barrel adjusters to achieve optimal shifting performance. These adjusters are small screws located on the derailleur housing. Turning them clockwise increases cable tension, while turning them counterclockwise decreases cable tension.
To fine-tune the barrel adjusters:
- Shift into the smallest cog on the cassette.
- Adjust the low-limit barrel adjuster until the chain is aligned with the smallest cog and there is no slack in the cable.
- Shift into the largest cog on the cassette.
- Adjust the high-limit barrel adjuster until the chain is aligned with the largest cog and there is no slack in the cable.
- Shift through all the gears and make micro-adjustments to the barrel adjusters as needed to ensure smooth and precise shifting.
The following table provides a more detailed guide to barrel adjuster fine-tuning:
Gear Adjustment Lowest gear (smallest cog) Adjust low-limit barrel adjuster until the chain is aligned with the smallest cog and there is no slack in the cable. Highest gear (largest cog) Adjust high-limit barrel adjuster until the chain is aligned with the largest cog and there is no slack in the cable. All gears Shift through all the gears and make micro-adjustments to the barrel adjusters as needed to ensure smooth and precise shifting. Chain Tension and Length
Ensuring proper chain tension is crucial for smooth shifting and avoiding premature wear on the drivetrain components. Here’s how to adjust chain tension on a Shimano derailleur:
Checking Chain Tension
Place the bike on a stand or level ground. Shift into the largest cog at the rear and the highest gear at the front. Lift the chain at a point halfway between the two chainrings. It should have approximately 5mm of slack when you let it go.
Adjusting Chain Tension
- If the chain is too loose, turn the barrel adjuster on the derailleur clockwise to shorten the chain.
- If the chain is too tight, turn the barrel adjuster counterclockwise to lengthen the chain.
Determining Chain Length
The correct chain length depends on the specific drivetrain configuration. However, you can estimate it using the following method:
- Shift into the largest cog at the rear and the smallest gear at the front.
- Wrap the chain around the chainrings and rear cogs. Ensure it’s taut, but not excessively tight.
- Join the ends of the chain. If they overlap for more than two links, the chain is too long.
If you’re unsure about the correct chain length, it’s best to consult a bike mechanic.
B-Screw Adjustment
The B-screw adjustment controls the distance between the idler pulley and the largest cog on the cassette. When properly adjusted, the idler pulley should be centered between the upper and lower pulleys, and the chain should run smoothly through the derailleur without any rubbing or skipping.
To adjust the B-screw, first shift the derailleur to the largest cog on the cassette. Then, look at the idler pulley from the side and turn the B-screw clockwise or counterclockwise until the idler pulley is centered between the upper and lower pulleys. You may need to make several small adjustments until the idler pulley is properly positioned.
Once the idler pulley is centered, shift the derailleur through all of the gears to ensure that the chain runs smoothly without any rubbing or skipping. If you notice any rubbing or skipping, fine-tune the B-screw until the issue is resolved.
B-screw adjustment table
Cog B-screw setting (mm) 11T 0.8-1.0 12T 1.0-1.2 13T 1.2-1.4 14T 1.4-1.6 15T 1.6-1.8 16T 1.8-2.0 17T 2.0-2.2 18T 2.2-2.4 19T 2.4-2.6 20T 2.6-2.8 21T 2.8-3.0 22T 3.0-3.2 23T 3.2-3.4 24T 3.4-3.6 25T 3.6-3.8 26T 3.8-4.0 27T 4.0-4.2 28T 4.2-4.4 29T 4.4-4.6 30T 4.6-4.8 31T 4.8-5.0 32T 5.0-5.2 34T 5.2-5.4 36T 5.4-5.6 38T 5.6-5.8 40T 5.8-6.0 42T 6.0-6.2 44T 6.2-6.4 46T 6.4-6.6 48T 6.6-6.8 50T 6.8-7.0 51T 7.0-7.2 52T 7.2-7.4 Park Tool Aids for Derailleur Calibration
To accurately calibrate your Shimano derailleur, you may want to consider utilizing the following tools from Park Tool:
Chain Checker CC-3.2
This tool enables you to determine whether your chain has reached a level of wear requiring replacement. It’s important to replace your chain at the right time, as a worn chain can accelerate the wear of your cassette and chainrings. By using the CC-3.2, you can avoid costly repairs in the future.
Derailleur Hanger Alignment Gauge DAG-2.2
The DAG-2.2 helps ensure that your derailleur hanger is properly aligned, which is crucial for the proper functioning of your derailleur. It’s recommended to use this tool after any accident or if you’ve noticed shifting issues, as the hanger may have become misaligned.
Chain Length Checker CC-4
The CC-4 allows you to determine the correct chain length for your bike. An improperly sized chain can cause shifting problems and wear on other components. By using the CC-4, you can ensure that your chain is the optimal length for your bike’s setup.
Cable Tension Gauge TM-1
The TM-1 assists in measuring the tension on the derailleur cable. Proper cable tension is essential for precise shifting. Using the TM-1, you can achieve the ideal cable tension for your specific setup, allowing for smooth and efficient shifting.
Spoke Tension Meter ST-1
Although not directly related to derailleur calibration, the ST-1 enables you to check the tension of your spokes. Proper spoke tension is important for the overall stability of your wheels and can indirectly affect shifting performance. By using the ST-1, you can ensure your wheels are tensioned correctly.
Troubleshooting Common Issues
Chain Rubbing on Derailleur Cage
Check the alignment of the rear derailleur. Use the barrel adjuster on the derailleur to fine-tune the position of the derailleur so that the chain runs smoothly.
Chain Skipping or Dropping
Ensure the chain is clean and lubricated. Inspect the chain for wear or damage. If necessary, replace the chain.
Difficulty Shifting Gears
9. Indexing the Rear Derailleur
Follow these steps to properly index the rear derailleur:
- Shift the rear derailleur to the smallest cog (highest gear).
- Use the barrel adjuster on the derailleur to tighten the cable tension until the chain just begins to rub against the next smallest cog.
- Shift to the next smallest cog (one up) and check that the chain is centered on the cog.
- If necessary, fine-tune the barrel adjuster until the chain is perfectly centered.
- Repeat steps 2-4 for all cogs on the cassette, moving up the gears.
- Ensure that the chain shifts smoothly between all cogs.
Other Issues
Inspect the derailleur cable for fraying or damage. Replace the cable if necessary.
Check the derailleur hanger for any bends or misalignment. If necessary, straighten or replace the derailleur hanger.
Maintaining Calibration and Shifting Performance
Regular maintenance is essential for keeping your Shimano derailleur performing at its best. Proper shifting relies on precise adjustments, and regular tuning ensures that the derailleur maintains its accuracy over time. Here are some important steps to maintain proper calibration and shifting performance:
1. Check Cable Tension
The cable tension plays a crucial role in shifting performance. If the cable is too loose, it can cause hesitation or missed shifts. Conversely, excessive tension can lead to stiff shifting or even damage to the derailleur. To adjust cable tension, follow these steps:
- Shift the derailleur to the highest gear (smallest cog).
- Check if the rear derailleur’s cage is parallel to the cog.
- If it’s not parallel, turn the barrel adjuster on the derailleur slightly to increase or decrease tension.
- Repeat the previous steps for the lowest gear (largest cog).
The ideal cable tension should allow for smooth and precise shifting across the entire gear range without excessive play or stiffness.
2. Check Limit Screws
Limit screws determine the extreme positions of the derailleur, preventing it from shifting beyond the smallest or largest cog. Misadjusted limit screws can cause the chain to fall off the cog or damage the derailleur. To adjust the limit screws:
- Shift the derailleur to the largest cog (highest gear).
- Turn the “H” limit screw inward until the chain just touches the largest cog.
- Shift to the smallest cog (lowest gear) and repeat the process with the “L” limit screw.
- Ensure that the chain doesn’t touch the derailleur body at either extreme.
3. Clean and Lubricate
Regular cleaning and lubrication of the derailleur and drivetrain components is essential for smooth and efficient shifting. Dirt, grime, and rust can accumulate over time, causing friction and hindering performance. To clean and lubricate your derailleur:
- Use a degreaser or bike cleaner to remove dirt and debris.
- Apply a suitable chain lubricant to the chain, cogs, and derailleur pivots.
- Wipe away excess lubricant and shift through the gears to ensure proper distribution.
4. Inspect Cables and Housing
Worn or damaged cables and housing can lead to sluggish or unreliable shifting. Inspect the cables and housing for any signs of fraying, rust, or kinks. If necessary, replace the affected components to restore smooth cable movement.
5. Adjust B-Screw
The B-screw adjusts the distance between the derailleur’s upper pulley and the largest cog. Proper adjustment ensures accurate shifting and prevents excessive chain wear. To adjust the B-screw:
- Shift the derailleur to the largest cog (highest gear).
- Turn the B-screw clockwise or counterclockwise until the upper pulley is directly in line with the center of the largest cog.
6. Check Chain Length
An improperly sized chain can contribute to shifting issues. A chain that is too short can cause the derailleur to struggle to shift to higher gears, while a chain that is too long can result in dropped chains or excessive wear. To check the chain length, refer to the manufacturer’s recommendations.
7. Inspect Gear Cogs
Worn or damaged gear cogs can affect shifting performance. Inspect the cogs for any signs of wear, such as uneven wear patterns or missing teeth. Replace any damaged cogs to ensure smooth and reliable shifting.
8. Align Derailleur Hanger
The derailleur hanger is the component that connects the derailleur to the frame. If the hanger is misaligned, it can cause the derailleur to shift poorly. To align the derailleur hanger:
- Use a derailleur alignment tool or a special gauge.
- Adjust the hanger until the derailleur cage is parallel to the largest cog.
9. Index Shifting
Indexing ensures that the derailleur moves the chain to each cog precisely when the shifter is actuated. To index the shifting:
- Shift the bike into the middle of the gear range.
- Use the lower limit screw to fine-tune the position of the upper pulley.
- Repeat this process for the upper limit screw.
10. Trouble-shooting Common Shifting Issues
If you encounter any shifting problems, refer to the following table for common issues and potential solutions:
Issue Possible Cause Solution Chain falls off the cog Misadjusted limit screws Adjust limit screws to prevent the chain from falling off. Difficulty shifting to higher gears Loose cable tension Increase cable tension by turning the barrel adjuster. Hesitation when shifting to lower gears Excessive cable tension Decrease cable tension by turning the barrel adjuster. Grinding noise when shifting Worn or damaged gear cogs Replace worn or damaged cogs. Sluggish shifting Dirty or worn cables Clean and lubricate cables. By following these steps regularly, you can ensure that your Shimano derailleur operates at its optimal level, providing precise and reliable shifting performance.
How to Caliber a Derailleur Shimano
A derailleur is a bike part that helps to change gears, and it’s important to keep it in good working condition. A well-calibrated derailleur will make your bike shift smoothly and efficiently, and it will also help to prevent chain drops. Here are the steps on how to caliber a derailleur Shimano:
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Shift the bike into the smallest gear (the one closest to the frame).
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Loosen the cable tension adjusting screw on the rear derailleur.
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Turn the barrel adjuster on the derailleur inward until the pulley cage is directly below the smallest gear.
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Tighten the cable tension adjusting screw until the chain has slight tension.
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Shift the bike into the largest gear (the one farthest from the frame).
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Loosen the limit screw on the rear derailleur.
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Turn the barrel adjuster on the derailleur outward until the pulley cage is directly above the largest gear.
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Tighten the limit screw until the chain has slight tension.
Once you have completed these steps, your derailleur should be calibrated and shifting smoothly. If you are still having problems, you may need to consult a bike mechanic.
People Also Ask About How to Caliber a Derailleur Shimano
How often should I caliber my derailleur?
It is a good idea to caliber your derailleur every few months, or more often if you ride your bike in a lot of dirt or mud. A well-calibrated derailleur will make your bike shift more smoothly and efficiently, and it will also help to prevent chain drops.
What are the symptoms of a derailleur that needs to be calibrated?
There are a few different symptoms that can indicate that your derailleur needs to be calibrated. These include:
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Difficulty shifting gears
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Chain drops
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Noisy shifting
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Gears that slip when you are pedaling
Can I caliber my derailleur myself?
Yes, it is possible to caliber your derailleur yourself. However, it is important to follow the instructions carefully and to be patient. If you are not comfortable working on your bike, it is best to take it to a bike mechanic.
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