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A bicycle is not just a simple mode of transportation, but also a machine that requires careful attention to its components to ensure a smooth and efficient ride. Among the most important components of a bike are the drivetrain and gear components. These essential parts work together to transfer power from the pedals to the wheels, making it possible for the rider to propel the bike forward.
In this article, we will discuss the importance of drivetrain and gear components and provide an overview of the various types available in the market. We will also explore the features and benefits of each type to help you make an informed decision when upgrading or replacing these components.
Understanding The Drivetrain
Before delving into the different types of drivetrains and gear components available for bicycles, it’s important to understand what a drivetrain is and how it works.
A drivetrain refers to the system that connects the pedals to the rear wheel of a bike. This system comprises various components, including the crankset, chain, cassette, derailleur, and shifters. These components work together to transfer power from the pedals to the rear wheel, propelling the bike forward.
The drivetrain is a critical component of any bicycle, as it determines its speed, efficiency, and overall performance. A well-maintained and high-quality drivetrain can help you achieve faster speeds with less effort, while a worn-out or low-quality drivetrain can make riding feel like a struggle.
Types of Drivetrains
Two main types of drivetrains are available for bicycles: internal and external.
Internal Drivetrain
Internal drivetrains are designed to be completely enclosed within the bike frame, providing a clean and sleek appearance. These drivetrains typically feature a single cog or a limited range of gears and are popular among commuters and urban riders who prioritize simplicity and ease of use.
The most common type of internal drivetrain is the single-speed drivetrain, which features a single cog and no derailleur. Single-speed drivetrains are easy to maintain and ideal for flat terrain, but may not provide enough gears for hilly/rough terrain or more demanding rides.
Another type of internal drivetrain is the internally geared hub (IGH) drivetrain, which features multiple gears enclosed within the rear hub of the wheel. IGH drivetrains are more complex than single-speed drivetrains but offer a wider range of gears for different riding conditions.
External Drivetrain
External drivetrains are designed to be mounted on the outside of the bike frame, allowing for greater customization and versatility. These drivetrains typically feature multiple cogs and a derailleur, which allows for more precise gear changes and a wider range of gears. They are usually called as per the number of cassette wheels like 10-speed groupset, 11-speed groupset, and 12-speed groupset.
The most common type of external drivetrain is the derailleur drivetrain, which features a chain that runs between multiple cogs on the rear wheel and a derailleur that moves the chain between the cogs. Derailleur drivetrains are popular among road cyclists and mountain bikers who require a wide range of gear to tackle various terrains. So usually road bike groupsets and mountain bike groupsets are external drivetrains.
A well-maintained and high-quality drivetrain is essential for any cyclist looking to maximize their speed, efficiency, and overall riding experience. Understanding the different types of drivetrains and gear components available can help you make an informed decision when upgrading or replacing these essential components.
In the next section of this article, we will discuss the various drivetrain components available for bicycles and how they can impact your riding experience.
Components of a Drivetrain
A bicycle’s drivetrain consists of several components that work together to provide a smooth and efficient ride. In this article, we will discuss the various components of a bicycle’s drivetrain.
Chainring:
The chainring is the front gear on a bike that is attached to the crankset. The size of the chainring determines the gear ratio of the bike. Bikes usually have two or three chainrings, and the rider can shift between them using the front derailleur. The chainring’s teeth come in different shapes and sizes, and the number of teeth on the chainring determines the gear ratio.
Cassette:
The cassette is the rear gear cluster on a bike that is attached to the rear hub. The cassette also has teeth of varying sizes, which determine the gear ratio. Bikes can have anywhere between 6 to 12 gears on the cassette, with 12-speed cassettes and 11-speed cassettes being more common on modern bikes. Lower-end bikes usually have 8-speed cassettes or 9-speed cassettes. The rider can shift between gears using the rear derailleur.
Chain:
The chain is the component that connects the chainring to the cassette and transfers power from the pedals to the rear wheel. The chain’s length is determined by the size of the bike frame and the number of gears on the bike. Keeping the chain clean and well-lubricated is important for smooth shifting and preventing wear.
Derailleurs:
The derailleurs are the components that move the chain between gears. There are two derailleurs on a bike – the front derailleur and the rear derailleur. The front derailleur moves the chain between the chainrings, while the rear derailleur moves the chain between the gears on the cassette. The derailleurs are operated by the shifters, which we will discuss next.
Shifters:
The shifters are the components that the rider uses to change gears. They are usually located on the handlebars, and the rider can shift gears by pushing or pulling on the levers. There are two types of shifters – the trigger shifters and the grip shifters. The trigger shifters have two levers that the rider can push or pull to change gears, while the grip shifters have a rotating dial that the rider can twist to change gears.
By understanding the different components of the drivetrain, riders can make informed decisions when choosing a bike or upgrading their current bike’s drivetrain.
Now that we have seen the drivetrain components, let’s explore each component in detail.
Chainring
The chainring is the component attached to the bicycle’s crank arms and contains teeth that mesh with the bicycle chain. The chainring transfers the pedaling force from the rider’s legs to the chain, which ultimately drives the rear wheel. There are several different types of chainrings, including:
– Round: The most common type of chainring, round chainrings have a consistent tooth profile around the ring’s circumference.
– Oval: Oval chainrings have an asymmetrical tooth profile that varies the resistance felt by the rider during the pedal stroke.
– Elliptical: Similar to oval chainrings, elliptical chainrings have a variable tooth profile optimized for the rider’s natural cadence.
The number of teeth on a chainring can vary depending on the intended use of the bicycle. Smaller chainrings typically have fewer teeth and are used for climbing or for riders who prefer a lower gear ratio. Larger chainrings have more teeth and are used for higher speeds or riders who prefer a higher gear ratio.
The materials used in chainring Manufacturing can vary widely, but the most common materials are aluminum and carbon fiber. Aluminum chainrings are more affordable and offer good durability and stiffness. Carbon fiber chainrings are lighter and more expensive but may need to be more durable.
Cassette
The cassette is a set of sprockets that are attached to the rear wheel of the bicycle. The cassette is responsible for providing the rider with a range of gear ratios to choose from. There are several different types of cassettes, including:
– Freewheel: A type of cassette that is threaded onto the rear hub of the bicycle.
– Cassette: The more modern design, the cassette is attached to the hub with a lockring.
The number of cogs on a cassette can vary depending on the intended use of the bicycle. Cassettes with fewer cogs are typically used for climbing or for riders who prefer a lower gear ratio. Cassettes with more cogs are used for higher speeds or riders who prefer a higher gear ratio.
The materials used in cassette manufacturing can vary widely, but the most common materials are steel and titanium. Steel cassettes are more affordable and offer good durability and stiffness. Titanium cassettes are lighter and more expensive but may need to be more durable.
Chain
The chain is the component that transfers power from the chainring to the cassette. There are several different type of chains, including:
– Road: This type of chain is designed for use on road bikes, these chains are typically narrower and lighter than other types of chains.
– Mountain: Designed for use on mountain bikes, these chains are typically wider and more durable than road chains.
The length of the chain is an important consideration when selecting a chain. A chain that is too short will not allow the rider to shift into the largest gears, while a chain that is too long will be prone to skipping and may cause damage to the derailleur.
The materials used in chain manufacturing can vary widely, but the most common materials are steel and titanium. Steel chains are more affordable and offer good durability and stiffness. Titanium chains are lighter and more expensive but may need to be more durable.
Derailleurs
Derailleurs are the components that are responsible for shifting the chain from one chainring or cog to another. There are two types of derailleurs: the front derailleur and the rear derailleur.
The front derailleur is responsible for shifting the chain between the chainrings. It is usually mounted on the seat tube and is operated by a shifter located on the handlebars. When the rider shifts to a higher gear, the front derailleur with triple or double chainrings moves the chain to a smaller chainring, while shifting to a lower gear moves the chain to a larger chainring.
The rear derailleur is responsible for shifting the chain between the cogs on the cassette. It is usually mounted on the rear derailleur hanger and is also operated by a shifter located on the handlebars. When the rider shifts to a higher gear, the rear derailleur moves the chain to a smaller cog, while shifting to a lower gear moves the chain to a larger cog.
The derailleurs work by using a mechanism that moves the chain laterally to align it with the desired chainring or cog. They are equipped with springs and pulleys that help to maintain tension on the chain and ensure that it does not fall off the chainring or cog.
When choosing a derailleur, it is important to consider factors such as compatibility with the drivetrain as there are a range of groupsets available, the number of gears, and the weight of the component. High-end derailleurs are usually made from lightweight materials such as carbon fiber, while entry-level derailleurs are made from heavier materials such as aluminum.
Shifters
Shifters are the components that allow the rider to change gears while riding. There are three main types of shifters: trigger shifters, grip shifters, and electronic systems of shifters.
Trigger shifters are the most common type of shifter, usually located on the handlebars. They consist of two paddles that the rider can push or pull to shift the gears up or down. They are easy to use and provide precise shifting.
Grip shifters, on the other hand, are located on the handlebar grip and are operated by twisting the grip to shift the gears up or down. They are popular among mountain bikers and provide quick and intuitive shifting.
Electronic shifters are the newest type of shifter and are becoming increasingly popular among road cyclists. Shifters in electronic groupset use electronic signals to shift gears instead of mechanical cables, which provides faster and more precise shifting due to wireless shifting being used. They are also more expensive than mechanical shifters and require regular charging.
When choosing a shifter, it is important to consider factors such as compatibility with the drivetrain, the number of gears, and the type of riding. High-end shifters are usually made from lightweight materials such as carbon fiber, while entry-level shifters are made from heavier materials such as aluminum.
Understanding Gearing:
Gearing refers to the relationship between the speed at which a cyclist pedals and the speed at which the wheels rotate. It is an important aspect of cycling that determines how easily a rider can pedal and the amount of power they can generate. Gearing can be adjusted to match the terrain and the rider’s strength, allowing for efficient and comfortable cycling.
What is Gearing and How It Works:
Gearing works by using different gear combinations to change the ratio between the pedals’ speed and the wheels’ speed. A bike’s gears are designed to provide a mechanical advantage, making it easier to pedal up hills and allowing for faster speeds on flat or downhill sections. The gears are controlled by a shifter, which moves the chain from one gear to another. This changes the gear ratio, affecting the amount of power needed to pedal and the bike’s speed.
Gear Ratios and Cadence:
Gear ratios are the ratios between the number of teeth on the front chainring and the rear cassette cogs. The ratio determines how much the pedals need to turn to rotate the wheel once. A higher gear ratio means that the bike travels further with each pedal stroke, but requires more effort. Lower gear ratios require more pedal strokes to travel the same distance but require less effort. The cadence refers to the number of pedal strokes per minute, and the ideal cadence is around 80-100 rpm for most riders. A lower cadence can cause strain on the knees, while a higher cadence can cause fatigue in the legs.
Components of Gearing:
Crankset:
The crankset is the component that connects the pedals to the bike’s frame. It consists of two or three chainrings, the toothed circles the chain wraps around. The crankset determines the number of gear options available to the rider. A standard crankset has two chainrings called double cranksets, while a triple crankset has three. When SRAM and Shimano introduced 10-speed drivetrains, cranksets with two chainrings with different chainring sizes became more popular than triple ones in mountain biking.
Double cranksets have a narrower gear range and less overlap, with a smaller inner ring (22-28 tooth) and a larger outer cog (34-36 tooth) that suits faster riding. Double cranksets are used from entry-level to high-end bikes but are becoming less popular. The triple crankset is the classic setup with three chainring sizes – a large outer ring of 42-44 teeth, a middle ring of 32-34 teeth, and a small inner ring of 22-24 teeth. It offers the widest range of gears, but gear ratios can overlap, and cross-chaining is a problem. Triple cranksets are no longer used on high-end mountain bikes and single or double cranksets are now popular. They’re disappearing from the entry-level market as well. The material used can be alloy or carbon fiber. The weight ratio of carbon fiber is higher in comparison to its strength.
Pedals:
Pedals are the component that the rider uses to apply force to the bike’s crankset. There are many types of pedals, including flat, clipless, and platform pedals. Clipless pedals are a popular choice for road cyclists because they allow for a more efficient transfer of power from the foot to the pedal.
Bottom Bracket:
The bottom bracket is the component that connects the crankset to the bike’s frame. It houses the bearings that allow the crankset to rotate smoothly. There are types of bearings as well, ceramic bearings are the higher-end ones. The type of bottom bracket used depends on the bike type and the rider’s preferences.
Freewheel:
The freewheel is the component that allows the rider to coast without pedaling. It consists of a set of ratcheting teeth that allow the wheel to rotate freely in one direction, but not in the other direction. The freewheel is located on the rear wheel of the bike.
So, the gearing system is an essential component of a bicycle’s drivetrain. Understanding how gearing works and how to select the right gear ratios is crucial to enjoying a comfortable and efficient ride. The crankset, pedals, bottom bracket, and freewheel are all critical components of the gearing system, and selecting the right components for your needs is key to optimizing your riding experience.
Maintenance and Care
Maintaining and caring for your bicycle’s drivetrain and gearing components is essential to ensure its longevity and optimal performance. Neglecting these components can decrease performance, safety hazards, and costly repairs. In this section, we will discuss the importance of maintenance and care for these components, provide tips for keeping them in good condition, and highlight signs of wear and tear that indicate it’s time for a replacement.
Importance of maintaining and caring for drivetrain and gearing components
A bicycle’s drivetrain and gearing components are subjected to a lot of stress and wear during use. Dirt, debris, and moisture can accumulate and cause friction, leading to premature wear and tear. Regular maintenance and care can help prevent this and keep your bike running smoothly. Neglecting these components can result in:
– Shifting problems: Worn or dirty components can cause difficulty in shifting gears, resulting in slower speeds, inefficient pedaling, and a less enjoyable ride.
– Chain wear: A stretched or worn chain can cause damage to the drivetrain components and result in expensive repairs. Basically, the chain retention rate becomes very low.
– Safety hazards: A malfunctioning drivetrain or gearing component can cause sudden stops, slips, and falls, leading to injuries.
– Costly repairs: Neglecting maintenance can lead to more significant problems and costly repairs down the road.
Tips for maintaining and caring for these components
Here are some tips for maintaining and caring for your bicycle’s drivetrain and gearing components:
Clean regularly
Regular cleaning is essential to keep your components in good condition. Use a soft brush or rag to remove dirt and debris from the chain, gears, and derailleur. Use a degreaser to remove stubborn grease and grime, and lubricate with a high-quality chain lubricant.
Check and adjust regularly
Regularly check and adjust the tension and alignment of your chain, derailleur, and gears. This ensures optimal performance and reduces the risk of wear and tear.
Replace worn components
If you notice signs of wear and tear, such as a stretched chain, worn cassette, or damaged derailleur, it’s time to replace the affected component. Ignoring these signs can lead to more significant problems down the road and result in costly repairs.
Signs of wear and tear and when to replace them
Here are some signs of wear and tear and when to replace the drivetrain and gearing components:
– Chain wear: A stretched chain can cause significant damage to the drivetrain components. Replace the chain if it’s stretched beyond 0.75% or if it shows signs of rust, corrosion, or damage.
– Cassette wear: A worn cassette can cause chain slip and shifting problems. Replace the cassette if the teeth are worn, broken, or bent.
– Derailleur wear: A worn or damaged derailleur can cause difficulty in shifting gears. Replace the derailleur if it’s bent, damaged, or has worn jockey wheels.
Mountain Bike Drivetrain
Shimano
Shimano, a Japanese manufacturer, offers the widest range of groupsets for mountain biking usually referred to as mountain bike drivetrain or mountain bike groupsets. Their groupsets for mountain bikes are categorized from the least expensive and advanced technologies due to expensive components used in advanced options. The hierarchy includes Shimano Tourney, Shimano Altus M2000, Shimano Acera M3000, Shimano Alivio M3100, Shimano Cues U6000, Shimano Deore M6100, M5100, M4100, Shimano SLX M7100, Shimano Deore XT M8050, Shimano Deore XT M8100, Shimano XTR M9050, and Shimano XTR M9100. Usually, entry-level mountain bikes have Shimano Tourney.
SRAM
SRAM’s mountain bike groupsets are divided into two families: single-chainring groupsets (with many having a ‘1’ in the name) and double or triple options. Similar to Shimano, SRAM also offers discipline-specific options like X01 DH.
SRAM’s most recent technology, Eagle, introduced 1x 12-speed Group. Eagle-level drivetrains have shared features that distinguish them from SRAM’s 1×11 groups, including an 11-50t, 10-51t Cassette, or 10-52t Cassette, larger 14-tooth jockey wheels, an improved ‘Type 3’ clutch mechanism in the rear derailleur, and a redesigned 1x-specific chainring with taller, curved teeth and a new profile intended to improve performance at the extreme ranges of the cassette.
SRAM’s groupsets are ordered from least to advanced technologies as follows:
– SRAM X3
– SRAM X4
– SRAM X5
– SRAM X7
– SRAM SX Eagle
– SRAM NX
– SRAM NX Eagle
– SRAM GX
– SRAM GX Eagle
– SRAM X1
– SRAM X01
– SRAM X01 Eagle
– SRAM X01 Eagle AXS
– SRAM XX
– SRAM XX1 Eagle
– SRAM XX1 Eagle AXS
– SRAM X0 T-Type Eagle AXS
– SRAM XX T-Type Eagle AXS
– SRAM XX SL T-Type AXS
SRAM continues to be a significant player in the mountain bike industry, providing a range of high-quality options for riders of all skill levels and disciplines.
Mountain bike groupsets usually offer a higher gear range than road bike groupsets due to the difference in terrain they are being used.
Road Bike Drivetrain
Shimano
Most road bikes have Shimano groupsets but may include other brands to reduce costs. However, Shimano is most popular as Road Groupsets. It offers different groupset options for various price points, ranging from Claris and Sora for entry-level bikes to Shimano Ultegra and Shimano Dura-Ace for high-end bikes. There is also Shimano 105 for mid-level bikes. Shimano Ultegra is similar to Shimano Dura-Ace in performance but lighter. Both have electronic shifting systems called Di2 Groupsets as well as mechanical groupsets. It also produces Shimano GRX, its first gravel bike groupset, in both mechanical and electronic groupset versions with hydraulic disc brakes. Each groupset has a series number, and parts may not be cross-compatible between different series. Shimano Ultegra & Shimano Dura-Ace are expensive groupsets.
SRAM
SRAM is a US-based brand that offers electronic and mechanical groupsets for bikes. Its wireless groupsets are SRAM Red eTap, SRAM Force eTap AXS, and SRAM Rival eTap AXS. These use the same battery, which can be charged by a USB cradle. You can add Blips to the SRAM Red and SRAM Force eTap AXS for extra control.
The mechanical groupsets include SRAM Apex, SRAM Rival, and SRAM Force. All models have the option for a single ring at the front and disc brakes. SRAM’s DoubleTap system allows you to shift gears with a single lever, and the AXS app can be used for customization and firmware updates. Single-ring options are usually weight saving options as groupset weights are on the higher end.
In 2019, SRAM launched the AXS groupsets with smaller chainrings and a 12-speed version with a 10-tooth smallest sprocket. The app is used to configure the system and for checking the battery status. Two new options: Wide chainset and XPLR, designed for gravel bikes.
SRAM AXS systems are compatible with SRAM Eagle AXS mountain bike groupsets, which allows for more versatility in gearing options.
Campagnolo
Campagnolo, also known as “Campag” or “Campy”, has a rich cycling heritage and is famous for inventing the rear derailleur and quick-release skewers. Their groupsets range from the entry-level 11-speed Centaur to the 12-speed system Chorus, Campagnolo Super Record, and Record, with the Campagnolo Super Record EPS being their most expensive electronic groupset and one of the wireless options. They have also teamed up with Magura to develop their disc brakes groupsets to offer faster and more effective braking in wet conditions. Campagnolo’s shifting system is unique, with a lever behind the brakes on the ‘Ergopower’ shifters and a thumb lever on the inside. Their systems are recognized for their distinctive ‘clunk,’ which the electronic system also provides. EPS is available at the Super-Record level and is powered by a rechargeable battery with an Interface Unit housed in the bar end. Configuration is done through the ‘MyCampy’ App wirelessly via Bluetooth (BLE) or ANT+.
In conclusion, maintaining and caring for the drivetrain and gearing components of your bicycle is essential for optimal performance and safety. Regular cleaning, checking, and replacing worn components can help prevent costly repairs and ensure an enjoyable riding experience. Remember to always consult a professional mechanic if you’re unsure about any maintenance or repair tasks.
In this article, we discussed the basics of bicycle drivetrain and gear components, including chainrings, pedals, bottom brackets, and freewheels. We also discussed the importance of maintaining and caring for these components, provided tips for keeping them in good condition, and highlighted signs of wear and tear indicating a replacement. Finally, we also saw some of the top groupsets available in the market. By following these tips, you can ensure that your bicycle’s drivetrain and gearing components last for years.
Frequently Asked Questions (FAQs)
Why do bikes have expensive groupsets?
Bicycle groupsets can be expensive due to the materials used, innovative features, and labor-intensive production methods. This, coupled with low-volume production and the need to cover manufacturing costs, can drive up prices. Higher-end groupsets can include features such as carbon fiber, electronic systems, and advanced disc brakes, which also contribute to their cost. Similarly, some watches are expensive due to the technology, engineering, time, and research involved in their production.
Expensive groupsets offer only marginal performance gains that mainly result from weight saving of groupset weights, as they often use durable carbon-fiber-reinforced alloys. These groupsets are also lighter, which can make you faster due to the overall weight saving in the system. When considering drivetrains, wheels, or complete bikes, a decrease in groupset weights typically results in a higher cost.
