Rear Derailleur Not Shifting

Last Updated on August 7, 2023 by Vinson Lozano

Are you tired of those annoying clicks and rattles every time you try to shift gears on your bike? Or even worse, does your rear derailleur refuse to shift at all, leaving you stuck in the wrong gear as you struggle to climb a steep hill? If so, you’re not alone! Many cyclists face rear derailleur not shifting issues at some point during their riding adventures. But, worry not, because we’ve got you covered in this blog post!

Join us as we dive into the common problems that cause rear derailleur shifting woes and provide you with easy-to-follow solutions that will have your bike shifting smoothly and quietly once again.

Say goodbye to the dreaded clicking and rattling, and shift gears with confidence as you conquer the most challenging terrains!

Introduction to Rear Derailleur Shifting Issues

Cycling enthusiasts know the smooth ride that comes with a well-functioning rear derailleur, but inevitably, shifting issues can still occur. In this comprehensive guide, we will explore the common problems that mountain bikers and road cyclists experience with rear derailleur shifting, and provide practical advice on diagnosing and fixing these issues.

  • Key aspects to consider while addressing rear derailleur shifting issues:
  • Familiarize yourself with the rear derailleur’s nomenclature to understand the role of each component.
  • Thorough troubleshooting of low and high gear shifting issues is essential for pinpointing the root cause of the problem.
  • Be aware of the proper B screw adjustment for efficient chain wrap.
  • Understand the functionality of barrel adjusters and cable housing to fine-tune your derailleur’s performance.

By acquiring detailed knowledge about rear derailleurs and their common problems, you can promptly diagnose and fix any shifting issues, ensuring a smooth ride and prolonging the life of your bike’s components.

Understanding Rear Derailleur Nomenclature

In order to effectively troubleshoot rear derailleur shifting problems, it’s essential to first understand the terminology associated with the rear derailleur and its various components. Here’s a simplified breakdown of the key terms:

  • Low limit screw: Adjusts how far the derailleur can move towards the lowest gear (biggest cog). It ensures proper alignment and prevents the chain from falling off the cassette.
  • High limit screw: Adjusts how far the derailleur can move towards the highest gear (smallest cog). Like the low limit screw, it maintains proper alignment and prevents the chain from shifting off the cassette and into the frame.
  • B screw (body-angle screw): Adjusts the distance between the upper pulley and the lowest gear, impacting chain wrap and low gear shifting.
  • Barrel adjuster: Found on the shifter, it allows for length adjustment of the cable housing, controlling cable tension to facilitate smooth shifting.

Understanding these terms will make it easier to diagnose and fix rear derailleur shifting issues more effectively.

Troubleshooting Low Gear Shifting Problems

Low gear shifting problems can be quite frustrating and may affect your overall cycling experience. Below are some potential causes and suggestions on how to troubleshoot these issues:

  • One of the most common reasons for low gear shifting problems is improper derailleur alignment. This is often due to having low cable tension, which prevents the derailleur from traveling enough to shift the gear to the lowest cog. To fix this, simply tighten the cable tension and align the rear derailleur correctly.
  • Limit screws can also cause issues if they are too tight or too loose. These screws determine the travel range of the rear derailleur and help prevent it from going too inward or too outward. Adjust the limit screws accordingly to ensure smooth shifting.
  • Lastly, a rusty or damaged shifting cable might be the culprit. This can cause the rear derailleur to get stuck, preventing it from shifting to the lowest gear. In such cases, it is best to replace the cable instead of trying to fix it.

In conclusion, maintaining proper alignment of the rear derailleur, adequate cable tension, and a healthy shifting cable are crucial for smooth low gear shifting. Regular maintenance and fine-tuning can help prevent most low gear shifting problems.

Troubleshooting High Gear Shifting Problems

High shifting problems can be a common occurrence when it comes to bicycle maintenance. These issues can result from various factors such as misaligned derailleurs, stretched cables, and other mechanical components that are out of adjustment. Here are some important points to consider when troubleshooting high gear shifting problems:

  • Derailleur alignment is a crucial factor in ensuring proper shifting. Make sure the derailleur’s mounting bolts, crankset, and cassette are fastened to the manufacturer’s recommended torque.
  • The high limit screw, as mentioned by Singletracks Mountain Bike News, is responsible for adjusting the limit of how far a derailleur can move towards the highest gear. When adjusted properly, the derailleur’s upper pulley should be directly in line with the highest gear to avoid any shifting problems.
  • Understanding the function of barrel adjusters is essential. Turning the adjuster counterclockwise from a rider’s perspective lengthens the cable housing, which effectively increases tension on the shift cable. This adjustment could potentially help resolve high gear shifting issues.

In conclusion, addressing high gear shifting problems usually involves a systematic examination of various components in the bike’s drivetrain. Regular maintenance and inspection of these components play a critical role in preventing and resolving shifting issues.

Adjusting the B Screw for Chain Wrap

Adjusting the B screw for chain wrap is essential in ensuring smooth and efficient shifting of your rear derailleur. The B screw, also known as the body-angle screw, is the mysterious third screw found on the back of your rear derailleur which controls the amount of space between the upper pulley and the lowest gear, ultimately affecting chain wrap and low gear shifting.

• Chain wrap refers to the amount of chain that interacts with a given cog in the cassette, from the point the chain first touches the cog until it leaves on its way to the chainring.
• Ideally, the upper pulley wheel should be 5-6mm away from the lowest cog for proper chain wrap.
• To adjust the B screw, turn it clockwise to increase the gap between the pulley and the lowest gear and counterclockwise to narrow the gap.

By properly adjusting the B screw, you can optimize chain wrap and ensure smooth, quiet shifting across all gears on your bike. This adjustment is crucial for maintaining the longevity and performance of your rear derailleur.

Understanding Barrel Adjusters and Cable Housing

By understanding how barrel adjusters and cable housing play a crucial role in rear derailleur shifting, you can ensure a smooth and efficient ride. Barrel adjusters are essential components that allow for adjustment and control of cable tension for precise shifting. They are usually found where the cable housing exits the shifter body, and on modern mountain bikes, they tend to be black or polished alloy in color. Some key points to keep in mind:

  • Barrel adjusters work by effectively changing the length of the cable housing, thereby adjusting the tension on the shift cable.
  • To increase tension, turn the adjuster counterclockwise from the rider’s perspective, which lengthens the cable housing. This helps shift the derailleur into lower gears more easily.
  • Conversely, turning the adjuster clockwise shortens the cable housing, reducing tension, and allowing the derailleur’s spring to pull it into higher gears more effectively.
  • Regular maintenance of cable housing is also essential as it ensures smooth, long-lasting performance of your bike’s shifting system. Inspect it periodically for any signs of wear, fraying, or damage.

By maintaining and adjusting barrel adjusters and cable housing, you’ll achieve optimal shifting performance and prevent any issues with your rear derailleur.

Checking for Chain Wear and Damage

Regular bike maintenance ensures smooth and efficient riding, and checking for chain wear and damage should be an integral part of your routine. Over time, the rollers and pins in your chain wear down, causing the links to stretch, and adversely affect your bike’s performance. In extreme cases, this can lead to damage to your cassette and chainrings, making replacements necessary. Here are some tips for keeping an eye on chain wear and damage:

  • Invest in a quality chain wear indicator tool, which measures the degree of wear and helps determine if it’s time to replace your chain.
  • Experts recommend checking your chain at least once a month or more frequently, depending on your riding habits and conditions.
  • Be proactive in replacing your chain at the recommended wear level (usually around 0.5% for 11 and 12-speed chains) to prevent further damage to your bike’s drivetrain.
  • Always inspect the chain for any visible signs of wear, such as rust, stiff links, or abnormal noise when pedaling.

By staying vigilant with chain wear and damage, you’ll save money on expensive replacements and enjoy a better ride overall.

Inspecting Housing and Cable for Damage

Inspecting the housing and cable for damage is a crucial step in troubleshooting rear derailleur shifting problems. As the factual data suggests, friction within the shifter cable and housing can lead to poor performance in shifting gears. Here are the best practices to follow when inspecting the housing and cable:

  • Start by shifting to the highest (smallest) gear and loosening the cable retention screw on the derailleur.
  • Check for friction by manually sliding the cable back and forth through the housing.
  • Keep an eye out for damaged or frayed ends in the housing where friction is most likely to occur.

As mentioned in the factual data, “Shifting problems may be caused by a gunked-up system.” In such cases, it is important to clean and lubricate the cable and housing components to ensure smooth and efficient gear shifting. Regular maintenance of these vital parts is key to a well-functioning rear derailleur system.

Diagnosing Bent Derailleur Hangers

Diagnosing bent derailleur hangers is a crucial step in maintaining your bicycle’s shifting performance. A bent hanger not only affects the quality of shifting but can also lead to further damage to the bike’s components. Here are some tips to diagnose bent derailleur hangers:

  • Visually inspect the derailleur hanger from the rear of your bike, checking for any misalignment or bending. Keep in mind, some hangers can look straight to the untrained eye and still be slightly bent.
  • Remove the hanger from the bike and check it against a flat surface, such as a table or workbench. A bent hanger will wobble or rock when nudged vertically.
  • Use a hanger alignment tool for the most accurate assessment. This tool will not only help you determine if the hanger is bent but also allows you to correct it by rebending the hanger.
  • Keep an eye out for symptoms such as inconsistent shifting across the cassette, chain skipping, or gears not working as they should, which may indicate a bent hanger.

Taking the time to diagnose bent derailleur hangers will ultimately help you maintain your bike’s optimal performance and avoid potential damage to other components.

Wrap-Up: Maintaining Your Rear Derailleur

In conclusion, maintaining your rear derailleur is essential for a smooth and efficient shifting experience while riding your bike. By paying attention to the key elements of rear derailleur upkeep, you can ensure a longer life and better performance. Here’s a quick wrap-up of the important aspects to consider:

  • Troubleshoot and address common derailleur problems, such as clicking sounds or gear slipping, by referring to expert guides and following proven solutions.
  • Regularly check components for wear and tear, like derailleur pulleys and shift cables, and replace them if necessary for proper functioning.
  • Keep an eye on the compatibility between the various components of your bike, such as the shifter, derailleur, and sprockets, to ensure smooth shifting.
  • Maintain cleanliness of the rear derailleur, sprockets, and chain for optimum functionality.
  • Routinely inspect your bike’s derailleur hanger; make sure it’s straight and firmly screwed.
  • Always pay close attention to adjustments involving the B screw, high limit screw, and low limit screw, as mastering these three parameters is crucial for precise rear derailleur performance.

By staying informed and actively maintaining your rear derailleur, you can enjoy a hassle-free riding experience and extend the lifespan of your bike’s components.

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