The Short Answer is:
Bicycle chains break for a variety of reasons, but the most common cause is wear. As a chain stretches out from use, the metal fatigues and becomes more susceptible to failure. Chains can also break due to impact damage from rocks or other objects, or if they are involved in a crash. Additionally, a damaged or twisted tooth on a chainring or cog can damage a link, leading to chain failure.
Bicycle chains are an essential component of a bike that keeps it moving. However, it can be frustrating when the chain breaks, leaving you stranded. There are several reasons bicycle chains break, and it’s essential to know them to prevent it from happening.
In this article, we will discuss the common reasons why bicycle chains break. Some of the reasons include wear and stretching, hard shifting, dirt and debris, and impact from rocks or bad falls.
Table of Contents
The Importance of a Well-Maintained Chain
A well-maintained bike chain is crucial for the smooth operation of a bicycle. Neglecting the chain can lead to damage or ruin of the entire drivetrain, including the chainrings and cassette, due to excessive abrasion.
Regular chain maintenance is necessary to prolong the life of both the chainring and the cassette. Cleaning the chain after every ride, especially after riding in wet conditions, is optimal.
If a chain is left without any maintenance for a week, there should be very few noticeable inconveniences, but after six months, the sound produced by most bike chains during every ride can be harsh due to the bushings, pins, and rollers inside the chain links going completely dry.
The chain of a bike is composed of hundreds of links, rollers, and plates, and there are moving parts in the chain that keep the bicycle moving around smoothly if they are well-maintained.
Regular maintenance of the chain is important to keep it moving around reliably and smoothly. Cleaning and lubricating the chain of a bike is a simple step that can be taken to maintain the bike.
There are several reasons why it is important to maintain a bike chain. Not cleaning the chain is a quick route to degrading all of the other parts of the drivetrain and reducing the overall longevity of the bike.
A well-greased and maintained chain contributes not only to immaculate and rapid shifting but also to prolong the life of both the chainring and the cassette.
Reasons Bicycle Chains Break
Bicycle chains can break due to various reasons. Here are some of the most common reasons why bicycle chains break:
1. Normal Wear and Tear
Normal wear and tear is one of the reasons why bicycle chains break. Over time, a heavily used chain will stretch out, and the links will loosen.
This stretching makes the chain more susceptible to metal fatigue, which can cause it to break. Wear on the chainrings and the rear gear cassette, a loose chain, and a sudden bad shift can also create the perfect mix for a broken chain.
A road bike chain will gradually wear and tear with use, and an overused chain transfers power poorly and can break. Therefore, it is important to inspect your bike before every ride for any signs of wear and tear, such as sagging and loose pins, and replace the chain when necessary.
2. Incorrect Installation or Tension
When it comes to bicycle chains, incorrect installation or tension can be a reason why they break. This can happen if the chain is not properly installed or if it is too loose or too tight.
If the chain is not installed correctly, it may not be able to handle the stress of pedaling and shifting gears, which can cause it to break.
Similarly, if the chain is too loose, it may come off the gears or skip, while if it is too tight, it may put too much stress on the chain and cause it to break.
Therefore, it is important to ensure that the chain is installed correctly and that it has the proper tension to avoid these issues.
3. Chain Stretch and Aging
Chain stretch and aging are common reasons why bike chains break. Over time, a heavily used chain will stretch out and the links will loosen, making the chain more susceptible to metal fatigue.
Chains can elongate over time, becoming looser and looser until they struggle to stay on the drivetrain’s cassette. If a chain has been ridden for a long time, it will actually stretch out, and as the chain wears, the chainrings and cassette (gears in the rear) will wear out as well.
As the chain stretches, the metal fatigues and becomes more susceptible to failure. Therefore, it is important to inspect your bike before every ride for any signs of wear and tear, such as sagging and loose pins, and to tighten the chain by removing a link or replacing the chain if necessary.
4. Poor Shifting Practices
Poor shifting practices can cause bicycle chains to break. When shifting gears, it is important to avoid putting too much pressure on the chain, as this can cause it to snap.
Additionally, shifting gears while pedaling too hard can also put unnecessary strain on the chain, leading to breakage. It is important to shift gears smoothly and gradually, rather than making sudden and forceful shifts.
To avoid poor shifting practices, it is important to maintain your bicycle and ensure that it is in good working order. Regular maintenance can help prevent issues with shifting and prolong the life of your chain.
One of the reasons why bicycle chains break is due to a phenomenon called cross-chaining. Cross-chaining occurs when a rider is in the smallest or largest cassette sprocket and the corresponding chainring at the same time.
This means using the smallest cassette sprocket and the smallest chainring, or the largest cassette sprocket and the largest chainring.
When a rider cross-chains, the chain is put under more strain and runs at a more extreme angle, potentially increasing friction and strain on the drivetrain components.
This can lead to increased wear and tear on the chain, making it more susceptible to breaking. Additionally, cross-chaining can cause the chain to rub against the front derailleur, resulting in noise and further strain on the drivetrain.
To avoid cross-chaining and reduce the risk of chain breakage, riders should aim for an optimum chain line for drivetrain efficiency.
This can be achieved by using the cogs towards the middle of the cassette, which results in a straighter chain line, making it more efficient and quieter.
6. Riding in Extreme Conditions
Riding a bicycle in extreme conditions can cause the chain to break. Extreme conditions include:
- Mud and Dirt: Riding in muddy or dirty conditions can cause the chain to become clogged with debris, leading to increased wear and tear. This can cause the chain to break over time.
- Rain and Water: Riding in the rain or through standing water can cause the chain to rust and corrode, weakening it over time. This can lead to the chain breaking unexpectedly.
- Extreme Temperatures: Extreme heat or cold can cause the chain to expand or contract, leading to increased stress on the chain. This can cause the chain to break if it is not properly maintained.
To prevent chain breakage in extreme conditions, it is important to regularly clean and lubricate the chain. Additionally, using a chain guard or cover can help protect the chain from debris and water.
7. Lack of Lubrication
Lack of lubrication is one of the reasons why bicycle chains break. A chain that is not lubricated enough will wear out faster and become more susceptible to metal fatigue, making it more likely to break.
The lack of lubrication can also cause the chain to rust, which can weaken the metal and cause it to break. Therefore, it is important to regularly lubricate your bike chain to keep it in good condition and prevent it from breaking prematurely.
8. Foreign Debris and Contaminants
Foreign debris and contaminants can also cause bicycle chains to break. Foreign debris refers to any object that unintentionally enters a product before or during the manufacturing process.
In the case of bicycle chains, foreign debris can include dirt, sand, stones, and other materials that can get stuck in the chain and cause it to break.
Contaminants, on the other hand, refer to any substance that can cause harm to the chain, such as rust or other corrosive materials. It is important to keep the chain clean and free of debris and contaminants to prevent it from breaking prematurely.
9. Impact or Damage
One of the reasons why a bike chain can break is due to impact or damage. Rocks, chunks of dirt, or bad falls can cause damage to the cassette, derailleurs, and the chain.
Impact damage to chains can be more difficult to repair than if the chain breaks due to wear. The reason is, that wear will typically only break one chain link, while impact can damage many.
Mountain bikers, in particular, are more susceptible to chain breaks due to the rough terrain and weather conditions they ride in. The teeth of the chainring can also get bent, which can cause the chain to break.
It is important to inspect your bike before every ride for any dents, misalignment, sagging and loose pins, or stuck pebbles you missed last time. Tightening the chain by removing a link or replacing the chain can help prevent further damage.
Preventive Maintenance for Chain Longevity
Preventive maintenance is key to extending the longevity of bicycle chains. One of the main reasons bicycle chains break is due to wear and tear caused by metal-on-metal contact.
To prevent this, regular cleaning and lubrication are necessary. The chain should be inspected and cleaned at least once a week to remove debris and dirt, and lubrication is essential for chain longevity.
In addition to daily tasks, there are a few once-a-week maintenance routines that should be performed, such as inspecting and lubricating all chains, sprockets, and components as required.
It is also important to check for signs of wear or elongation and to replace worn parts in a timely manner to avoid damage to the chain and other components.
Keeping spare parts on hand, such as sprockets, motors, and belts, can also ensure prompt replacement in case of part failure. By conducting regular maintenance, the lifespan and performance of bicycle chains can be maximized.
Frequently Asked Questions Related to the Topic:
What happens when bicycle chain breaks?
When a bicycle chain breaks, the bike becomes inoperable and the rider is unable to pedal. The chain can break for several reasons, including wear, impact damage, or improper installation.
If the chain breaks due to wear, it is likely that the chain has stretched out and become more susceptible to failure. Impact damage to chains can be more difficult to repair than if the chain breaks due to wear, as it can damage many links in the chain.
When a chain breaks, it is usually a sign of a larger issue, such as worn chainrings or cassettes. To fix a broken chain, the rider can use a chain breaker tool to remove the broken link and reattach the chain.
However, it is important to note that a broken chain usually means that a new chain is needed, as old chains expand and wear down over time.
How often do bicycle chains break?
The frequency at which bicycle chains break can vary depending on several factors, including the quality of the chain, how well it is maintained, and how often it is used.
Chains are a consumable part of the bicycle drivetrain and will wear out over time. As the internal parts of the chain, the rivets and rollers, begin to wear out, the chain can mesh poorly with cogs and chainrings, causing poor shifting, premature wear to the cogs, and even skipping over the cogs.
It is recommended to replace a worn chain when it reaches the 0.75% stretch mark. However, chains don’t wear evenly, so it’s best to take measurements on at least three different parts of the chain for the most accurate result.
Conclusion on Reasons Bicycle Chains Break
In conclusion, there are several reasons why a bicycle chain can break or get damaged. The most common reasons are when the chain is under too much tension, it gets bent or twisted, it’s worn and stretched out, or it takes a direct impact.
A heavily used chain will stretch out over time, and the links will loosen, making the chain more susceptible to metal fatigue. Wear on the chainrings and the rear gear cassette, a loose chain, and a sudden bad shift create the perfect mix for a broken chain.
Bent cogs can fail to take up the chain and may cause twisting and jams, which, under the stress of pedaling, can make the bike chain break. The impact from rocks, chunks of dirt, or bad falls are other reasons a bike chain can break.
To prevent these occurrences, it’s essential to inspect your bike before every ride for any dents, misalignment, sagging and loose pins, or stuck pebbles you missed last time. If you’re unlucky enough to run into one of these issues, you can fix your chain on the trail to get you moving again.