The chainstay is the part of the bike frame that connects the bottom bracket (where the pedals are attached) to the rear axle (where the rear wheel is attached). It is usually made of metal (such as steel, aluminum, titanium, or carbon fiber) and can have different shapes and lengths depending on the type and design of the bike.
The chainstay can affect how the bike handles, accelerates, climbs, descends, corners, and absorbs shocks, and also influences the bike’s geometry, weight distribution, stiffness, clearance, and aesthetics.
Now you may wonder how these happen, right?
No worries. In this article, we will help you find the answers, starting from how chainstay works, to what unique features the chainstay has and how each of them affects the bike performance.
Let’s dive right in.
How Chainstay Works
The chainstay is a crucial component of the drivetrain system that converts your pedaling force into the rotational motion of the rear wheel. It is connected to the bottom bracket by a crankset, which consists of two arms with pedals and one or more chainrings. The chainstay is also connected to the rear axle by a cassette, which consists of several sprockets of different sizes. A chain links the chainrings and the sprockets together and wraps around them as you pedal.
As you pedal, the force is applied to the chainring through the pedals and crankset. The chainring then rotates, causing the chain to move. This movement of the chain transfers the power to the rear wheel through the chainstay.
One of the key functions of the chainstay is to act as a lever that amplifies or reduces the torque applied by the pedals, depending on the ratio of the chainring and sprocket sizes. For example, if you are in a high gear (larger chainring and smaller sprocket), the chainstay will amplify the torque, allowing you to generate more power and speed. Conversely, in a low gear (smaller chainring and larger sprocket), the chainstay will reduce the torque, giving you more control and ease of pedaling.
However, for bikes with different chainstays, you may have different cycling experiences, because of them having different features. Among these chainstay features, the chainstay length has the biggest impact on the bike’s performance.
Chainstay length refers to the distance from the center of the rear axle of the bike to the center of the bottom bracket.
The chainstay length plays a crucial role in determining the wheelbase and weight distribution of the bike. A shorter chainstay length results in a shorter wheelbase and a more rearward weight distribution. On the other hand, a longer chainstay length leads to a longer wheelbase and a more forward weight distribution. These factors have a significant impact on how the bike performs.
A bike with a shorter chainstay length is more agile, responsive, and easier to accelerate. The shorter wheelbase allows for quicker and more nimble handling, making it ideal for maneuvering tight corners and navigating technical terrain. Additionally, the rearward weight distribution enhances power transfer, giving you a snappy and efficient ride experience.
Conversely, a bike with a longer chainstay length offers increased stability and smoothness. The longer wheelbase provides a more stable platform, especially at high speeds and during descents. The forward weight distribution helps with maintaining speed and provides a solid and predictable feel on the road or trail.
In addition to influencing overall bike performance, chainstay length also affects the handling characteristics of a bike. Let’s take a closer look at how it influences steering geometry and trail.
A shorter chainstay length results in a steeper steering geometry and a shorter trail. This combination makes the bike more nimble, maneuverable, and easier to turn. It excels in tight turns, quick changes of direction, and technical sections where quick reflexes are required.
Conversely, a longer chainstay length leads to a slacker steering geometry and a longer trail. This setup provides stability, predictability, and improved tracking. It’s ideal for fast descents, sweeping curves, and long-distance rides where stability and comfort are key.
Comfort is a crucial factor to consider when choosing a bike, especially for long rides or rough terrains. The chainstay length influences comfort in two significant ways: vibration damping and tire clearance.
A shorter chainstay length typically results in less vibration damping and less tire clearance. This can make the bike stiffer, harsher, and more prone to transmitting road or trail vibrations to the rider. Additionally, the reduced tire clearance limits the size of tires, which can affect the bike’s ability to absorb impacts and provide a smooth ride.
On the other hand, a longer chainstay length offers more vibration damping and more tire clearance. This results in a softer, smoother, and more comfortable ride, as the frame can better absorb shocks from the road or trail. The increased tire clearance allows for larger tires, which enhances comfort by providing more cushioning and better traction.
The chainstay length also has a direct impact on the bike’s handling, cornering, and maneuverability. Let’s explore how different chainstay lengths affect these aspects.
With a shorter chainstay length, the bike becomes more nimble and responsive. It’s easier to initiate quick turns, navigate tight corners, and change direction with precision. Additionally, the shorter chainstay length makes it easier to lift the front wheel off the ground, which can come in handy for hopping over obstacles or performing tricks.
Conversely, a longer chainstay length provides stability and predictability. It enhances the bike’s ability to maintain a straight line, especially at high speeds or on rough terrain. However, the longer chainstay length makes it slightly harder to lift the front wheel off the ground, which can be a challenge when climbing steep hills or clearing large gaps.
The chainstay length also affects the bike’s geometry, weight distribution, and center of gravity. Let’s explore how different chainstay lengths influence these aspects.
A bike with a shorter chainstay length tends to have a more compact and aggressive geometry. This can improve aerodynamics and pedaling efficiency, making it ideal for riders who prioritize speed and performance. However, the shorter chainstay length may reduce comfort and stability, particularly on longer rides or rough terrain.
On the other hand, a bike with a longer chainstay length offers a more relaxed and comfortable geometry. This prioritizes stability and shock absorption, making it suitable for riders who prefer a smoother and more comfortable ride. However, the longer chainstay length may slightly reduce aerodynamics and pedaling efficiency.
Lastly, the chainstay length also impacts the bike’s stiffness, clearance, and aesthetics. Let’s take a closer look at these factors.
A shorter chainstay length often results in a stiffer and lighter bike frame. This enhances responsiveness, acceleration, and power transfer. However, the reduced clearance limits the bike’s versatility, as there may not be enough space for larger tires, fenders, racks, or suspension systems. From an aesthetic standpoint, a shorter chainstay length gives the bike a sleek and modern appearance, which can appeal to riders looking for a sporty and aggressive style.
A longer chainstay length provides a more flexible and forgiving bike frame. This improves comfort, stability, and shock absorption, making it ideal for long rides or rough terrains. Additionally, the increased clearance allows for larger tires, fenders, racks, or suspension systems, enhancing the bike’s versatility. From an aesthetic standpoint, a longer chainstay length gives the bike a classic and traditional look, which may appeal to riders who prefer a relaxed and comfortable style.
To make it clearer, here is the summary of the benefits and drawbacks for different chainstay length.
Pros and Cons of Different Chainstay Length
Shorter chainstays, typically around 40-42 cm, offer a nimble and maneuverable ride. These shorter chainstays make it easier to turn and navigate tight corners. They also provide a more rearward weight distribution, which can result in better traction and balance. This is especially beneficial for riders who enjoy tackling technical trails or riding aggressively.
Additionally, shorter chainstays make it easier to lift the front wheel for manuals, wheelies, and bunny hops. This can be advantageous for riders who enjoy tricks or need to navigate obstacles on the trail. Shorter chainstays are also preferred by racers or sprinters on smooth roads or trails, as they allow for quick acceleration and efficient power transfer.
However, there are some downsides to shorter chainstays. They tend to be less stable and predictable, making it more challenging to balance at higher speeds. They also provide less forward weight distribution, which can result in less effective braking and cornering.
Additionally, shorter chainstays generally have less tire clearance and vibration damping, which can lead to a harsher and less comfortable ride. They are also more prone to punctures, as they offer less space for larger tires.
On the other end of the spectrum, longer chainstays, typically around 45-50 cm, offer a more stable and predictable ride. The longer chainstays provide a more forward weight distribution, improving braking and cornering performance. They also offer more tire clearance, allowing for the use of larger tires, which can enhance traction and provide a more comfortable ride by absorbing more vibrations.
Longer chainstays are also more versatile and adaptable, making them suitable for touring or cruising on varied roads or trails.
However, longer chainstays are not as nimble or maneuverable as shorter chainstays. They require more effort to turn and navigate tight corners. The rearward weight distribution is not as pronounced, which can result in slightly worse traction and balance. Lifting the front wheel for tricks or obstacles may also be more challenging with longer chainstays.
Lastly, longer chainstays are generally not preferred by racers or sprinters on smooth roads or trails, as they can hinder quick acceleration and efficient power transfer.
For those seeking a balance between agility and stability, medium chainstays, typically around 42-45 cm, are a good option. They offer a compromise between the benefits of shorter and longer chainstays.
Medium chainstays provide a balance between rearward and forward weight distribution, resulting in a good compromise for traction, balance, braking, and cornering. They also offer a balance between tire clearance and vibration damping, providing a comfortable ride without sacrificing performance. Medium chainstays are suitable for mixed terrain or gravel riding, where versatility is key.
However, they are not as agile as shorter chainstays or as stable as longer chainstays. They may not be as specialized or optimized for specific riding styles or preferences.
How to Measure Chainstay Length
By measuring the chainstay length, you gain valuable insight into the geometry of your bike frame. This information can also be useful when considering bike fit, frame sizing, or when comparing different bike models.
1. Prepare your bike and tools
Before you begin, make sure your bike is in a stable position with both wheels touching the ground and parallel to each other. You’ll need a tape measure or a ruler and a flat surface to place your bike on.
2. Find the center of the bottom bracket
The bottom bracket is the part of the bike frame where the crank arms meet. To locate the center of the bottom bracket, look for the point where the crank arms come together. You can mark this spot with a pen or a sticker to make it easier to measure later.
3. Locate the center of the rear axle
The rear axle is where the rear wheel attaches to the frame. Find the center point of the rear axle and mark it with a pen or a sticker. This will be the second reference point for measuring the chainstay length.
4. Measure the distance between the marks
Using your tape measure or ruler, measure the distance between the center of the bottom bracket and the center of the rear axle. Make sure to measure along the centerline of the bike frame. Record this measurement in centimeters or inches.
5. Check for accuracy and symmetry
To ensure accuracy, repeat the process on both sides of the bike. Measure the distance between the center of the bottom bracket and the center of the rear axle on both the left and right sides. Compare the measurements to check for symmetry. If the measurements are not equal, double-check your measurements and make any necessary adjustments.
How to Adjust Chainstay Length
Depending on your riding style and preferences, you may want to adjust the chainstay length to optimize your bike’s performance. And here are three working methods.
Method 1: Adjustable Dropout System
One method for adjusting chainstay length is to use a bike frame with an adjustable dropout system. This system allows you to slide the rear axle forward or backward along a slot on the frame, effectively changing the chainstay length.
To use this method, you’ll need a compatible frame with adjustable dropouts. Start by loosening the bolts that secure the rear axle to the frame. Then, slide the rear axle along the slot until you reach your desired chainstay length. Make sure to tighten the bolts securely.
After adjusting the chainstay length, it’s important to check the alignment of your rear wheel with the front wheel. Ensure that the rear wheel is centered on the frame and that the chain tension and brake alignment are adjusted accordingly. This method is relatively easy and quick, but it does require a compatible frame and dropout design.
Method 2: Different Wheel Size
Another method for adjusting chainstay length is to use a different wheel size. Swapping your existing wheel with one that has a different diameter or width can effectively change the effective chainstay length.
For example, if you have a bike with 700c wheels and a 25 mm tire, you could switch to a 650b wheel with a 47 mm tire. This change would shorten your effective chainstay length by about 1 cm (0.4 inches). However, it’s important to ensure that the new wheel size fits your frame without rubbing against any parts or compromising clearance or geometry.
Method 3: Frame Modification
The third method for adjusting chainstay length is also the most challenging and risky. It involves modifying your existing frame by cutting or welding new tubes or joints to change the actual chainstay length.
Modifying a frame requires advanced skills in metalworking and bike building, as well as access to specialized tools and equipment. It’s crucial to be aware of the potential safety hazards and legal issues involved in altering the frame structure and integrity. This method allows you to customize your frame according to your preferences and needs, but it’s not recommended for beginners or those without extensive experience.
Remember, each method has its own set of requirements and considerations. If you’re unsure or uncomfortable with making adjustments yourself, it’s always best to consult a professional bike mechanic who can guide you through the process.
Besides chainstay length, the chainstay shape is also a big one to affect the chainstay capability. There are four main types of chainstay shapes that are commonly used on different types of bikes. They are straight chainstays, curved chainstays, elevated chainstays, and asymmetrical chainstays.
Let’s start with the most basic and commonly used type of chainstay shape: the straight chainstay. As the name suggests, these chainstays run in a straight line from the bottom bracket to the rear axle. They are straightforward to manufacture and offer good stiffness and efficiency. Straight chainstays provide a direct power transfer from your pedaling motion to the rear wheel, resulting in a responsive and fast ride.
However, straight chainstays do have their limitations. Due to their straight design, they may restrict tire clearance, limiting the size of tires you can use on your bike. Additionally, they may also limit the chainring size or suspension travel, depending on the bike’s design. So, while straight chainstays excel in simplicity and efficiency, they may not be the best choice if you’re looking for more versatility or tire options.
Next up, we have curved chainstays. Unlike straight chainstays, curved chainstays are bent or curved in some way to create more space for the tire, chainring, or suspension. These curves can be upwards, downwards, sideways, or a combination of directions, depending on the bike’s design.
Curved chainstays offer several benefits, including improved tire clearance, allowing you to use wider tires for added comfort and traction. They can also provide more space for larger chainrings, enabling you to tackle steeper climbs. Additionally, the curves in the chainstays can enhance the bike’s compliance, absorbing road vibrations and providing a smoother ride.
However, curved chainstays do come with a tradeoff. The bending or curving of the chainstays adds complexity and cost to the manufacturing process. This can result in a slight reduction in stiffness and efficiency compared to straight chainstays. Nevertheless, if you prioritize comfort, versatility, and performance over absolute efficiency, curved chainstays can be a great choice for your bike.
Moving on to more specialized chainstay shapes, we have elevated chainstays. These chainstays are raised above the level of the bottom bracket to avoid interference with the chain or the suspension. You’ll typically find elevated chainstays on mountain bikes or gravel bikes that have large tires, wide cassettes, or full suspension systems.
Elevated chainstays offer significant benefits when it comes to navigating rough terrain. By raising the chainstays, bike manufacturers can increase tire clearance, allowing you to tackle challenging trails with confidence. The additional space also accommodates larger chainrings, enabling you to power through technical climbs. Moreover, elevated chainstays can enhance the bike’s traction, thanks to the increased clearance for mud and debris.
However, it’s important to note that elevated chainstays come with some drawbacks. The design is very challenging and costly to manufacture, making bikes with elevated chainstays more expensive. Additionally, the raised position of the chainstays may compromise the strength and durability of the bike, especially in high-stress situations. Nevertheless, if you’re a mountain biker or gravel enthusiast seeking maximum clearance and traction, elevated chainstays can be a game-changer for your off-road adventures.
Last but not least, we have asymmetrical chainstays. As the name suggests, these chainstays are different on each side of the bike to accommodate different components or features. Asymmetrical chainstays are commonly found on bikes equipped with disc brakes, belt drives, or single-speed drivetrains.
The main advantage of asymmetrical chainstays is their ability to accommodate specific components or features. For example, the asymmetrical design allows for optimal placement of the disc brake caliper, ensuring precise and efficient braking performance. It can also provide clearance for wider belt drives or create a symmetrical chainline for single-speed drivetrains.
However, the manufacturing process for asymmetrical chainstays is complex and costly, resulting in higher-priced bikes. Additionally, the asymmetry may affect the balance and symmetry of the bike, leading to potential handling differences. Nonetheless, if you’re seeking the benefits of disc brakes, belt drives, or single-speed setups, asymmetrical chainstays will provide the functionality you need.
Chainstay Varying Across Different Types of Bikes
For different bike types, they will have different chainstay length and shape, because of their different frame geometry and cycling purposes.
If you’re a road cyclist, you’ve likely noticed that road bikes have relatively short and straight chainstays. Why is that? Well, road bikes are designed for speed and agility on smooth surfaces. The shorter chainstay length helps maximize power transfer and acceleration, allowing you to ride faster. Typical road bike chainstay length ranges from 40 to 42 cm (15.7 to 16.5 inches), providing a balanced combination of speed and stability.
But there’s more to it! Some road bikes have curved or dropped chainstays. Why? These design variations serve different purposes. Curved chainstays increase tire clearance, allowing for the use of wider tires, which can enhance comfort and traction. On the other hand, dropped chainstays help reduce weight or improve aerodynamics, making the bike more efficient in cutting through the wind. So, whether you prefer tire clearance, weight reduction, or increased aerodynamics, there’s a road bike design out there to suit your needs.
Now, let’s shift our focus to mountain bikes. Mountain bikes are built to handle rough terrains and provide stability and control to the rider. As a result, they typically have longer and curved chainstays. The longer length creates a more stable platform, allowing the rider to navigate challenging trails with confidence. Typical mountain bike chainstay length ranges from 42 to 46 cm (16.5 to 18.1 inches), providing the necessary stability and traction for off-road adventures.
But wait, there’s more to the story! Some mountain bikes have elevated or asymmetrical chainstays. Why? The elevated chainstay design helps avoid interference with suspension systems, ensuring smooth and uninterrupted travel over bumps and obstacles. Asymmetrical chainstays, on the other hand, accommodate wider tires or larger sprockets, enhancing the bike’s capability to handle diverse terrains. So, whether you’re conquering rocky trails or bombing down descents, mountain bikes are designed to handle it all.
What about the hybrid bikes, the versatile workhorses of the cycling world. Hybrid bikes are designed to offer a blend of speed, comfort, and versatility, making them suitable for various riding conditions. As such, hybrid bikes have moderately long and straight chainstays. This design strikes a balance between speed and stability, ensuring a smooth and efficient ride on mixed surfaces. Typical hybrid bike chainstay length ranges from 43 to 45 cm (16.9 to 17.7 inches).
But hold on, there’s a twist! Some hybrid bikes come with slightly curved or dropped chainstays. Why? These design variations accommodate wider tires, fenders, or racks, adding extra versatility to the bike. So, whether you’re commuting to work, cruising on bike paths, or exploring unpaved trails, hybrid bikes are designed to handle it all.
Last but not least, let’s explore gravel bikes, the adventurers’ favorite. Gravel bikes are designed to tackle unpaved roads, combining the agility of a road bike with the stability of a mountain bike. To achieve this balance, gravel bikes have moderately long and curved chainstays. The longer length adds stability, allowing the rider to navigate unpredictable terrains with ease. Typical gravel bike chainstay length ranges from 42 to 44 cm (16.5 to 17.3 inches).
For the shape feature, some gravel bikes feature dropped or asymmetrical chainstays. Why? These design variations aim to increase tire clearance, reduce weight, or improve aerodynamics, enhancing the bike’s off-road performance. So, whether you’re exploring gravel roads, tackling challenging terrains, or embarking on multi-day adventures, gravel bikes are built to handle it all.
The chainstay is an important part of the bike frame that connects the bottom bracket to the rear axle. It affects how the bike performs, feels, and looks in various ways.
But, there is no one-size-fits-all answer for the ideal chainstay length as it depends on many factors such as your bike type, riding style, terrain, and personal preference. The best way to find out what chainstay length works for you is to try different bikes or options and see how they affect your riding experience. You can also consult with a bike expert or a bike fitting service to get some professional advice and guidance on how to optimize your chainstay length.
What do you think about chainstay length? Do you have a preferred chainstay length for your bike? Share your thoughts and experiences in the comments below.