If you’re a cyclist, you’ve probably heard of thru axles and quick releases. These are the mechanisms that attach your wheels to your bike frame and fork. While both options have their merits, it’s important to understand the differences between them to choose the one that best suits your needs and preferences.
In this article, we’ll delve into the world of thru axles and quick releases, compare their features and performance, pros and cons, and help you understand them well and make an informed decision in the future.
What is A Quick Release
Back in 1927, Italian bicycle racer Tullio Campagnolo was frustrated by the time-consuming process of changing gears during a race. At that time, bicycles only had one cog on each side of the rear hub, requiring riders to stop, flip the wheel over, and reattach it to change gears. Campagnolo lost a race because his hands were too cold to operate the wingnuts that held the wheel in place. This experience led him to invent the quick release skewer.
Campagnolo’s invention consisted of a rod with a lever-operated cam system that could quickly secure or release the wheel. This innovation allowed riders to change flat tires quickly and get back in the race without losing valuable time. It revolutionized the cycling world and became the standard method for attaching wheels to bikes for about 75 years.
How Does A Quick Release Work
A quick release (also called quick release skewer) typically consists of four main parts: a rod or skewer, a lever, a nut, and two springs. The rod is threaded on one end and goes through the hollow axle of the wheel. The lever is attached to the rod and operates a cam assembly on the other end. The nut is threaded on the rod and secures the skewer to the fork or frame. The conical springs are placed on the rod between the lever and the nut to keep the skewer centered and prevent it from loosening.
To attach a wheel using a quick release skewer, you need to follow a few simple steps. First, open the lever and unscrew the nut until it is loose enough to fit into the dropout of the fork or frame. Then, insert the rod through the axle of the wheel and align it with the dropout on the other side. Make sure that the springs are facing outward, with the narrow end pointing toward the wheel.
Next, tighten the nut by hand until it is snug against the dropout. Finally, close the lever by pushing it down and toward the wheel. The cam mechanism inside the lever will create a clamping force that securely holds the wheel in place. When the lever is closed, it should be parallel to the bike frame. You should feel some resistance when closing the lever, indicating that the wheel is securely attached.
To detach the wheel, simply reverse the process. Open the lever by pulling it up and away from the wheel, unscrew the nut by hand, and remove the rod from the axle. With the quick release skewer, wheel removal and replacement are quick and hassle-free.
What Standards Do Quick Release Skewers Have
There are different standards for quick release skewers depending on the type of bike and the width of the hub. Some of the common standards are :
- Rim brake road bikes: The front axle is usually 100mm wide and 9mm in diameter, while the rear axle is usually 130mm wide and 10mm in diameter. The skewer is 5mm in diameter and passes through the hollow axle.
- Disc brake road bikes: The front axle is usually 100mm wide and 9mm in diameter, while the rear axle is usually 135mm wide and 10mm in diameter. The skewer is 5mm in diameter. This standard is similar to the traditional road bike standard, but with an increased rear axle width to accommodate the disc brake rotor.
- Mountain bikes: The front axle is usually 100mm wide and 9mm in diameter, while the rear axle is usually 135mm wide and 10mm in diameter. The skewer is 5mm, too.
What is A Thru Axle
Still, let’s start with a bit of history. Thru axles were developed in the late 1990s as a response to the increasing demands of mountain biking and the introduction of disc brakes. Traditional quick release skewers, which had been the standard for decades, proved to be less than ideal for the rigors of off-road riding. They were prone to bending, breaking, or even ejecting from the fork or frame under the stress of big jumps and rough terrain.
Thru axles (also called through axles), on the other hand, offered a stronger and more secure way to hold the wheels in place. They were first invented for downhill and freeride bikes, where the need for stability and reliability was paramount. Since then, they have become increasingly popular across various disciplines, including mountain biking and disc brake road cycling.
How Does A Thru Axle Work
So, what exactly is a thru axle, and how does it work? In simple terms, a thru axle is a large bolt that passes through the hub and the fork or frame of the bike, securing the wheel in place. It replaces the traditional quick release skewer and provides a more robust connection between the wheel and the frame.
Thru axles typically have a larger diameter than quick release skewers, usually measuring 12mm, 15mm, or 20mm, depending on the type of bike and the width of the hub. They also feature a lever that can be tightened or loosened by hand, similar to quick release skewers.
A typical thru axle consists of four main parts:
- A Thru axle: This is a long metal rod with threads on one or both ends. It passes through the hub and the fork or frame and holds the wheel securely in place.
- A Lever: Attached to the thru axle, the lever allows for easy tightening and loosening. Depending on the design, the lever may be fixed or removable.
- A Nut or threaded insert: Situated on the opposite side of the lever, the nut or threaded insert receives the threads of the thru axle. It can be integrated into the fork or frame or be separate and replaceable.
- A Washer or spacer: Sometimes used between the lever and the fork or frame, the washer or spacer helps adjust the fit and alignment of the wheel.
What Standards Do Thru Axles Have
There isn’t a one-size-fits-all approach for the thru axles to fit a bicycle. Different types of bikes and hubs require different specifications. But here are some of the common standards you might come across:
- Downhill and freeride bikes: These typically use a front axle that is 110mm wide and 20mm in diameter, while the rear axle is 150mm wide and 12mm in diameter. These were the original standards for thru axles, designed to withstand the demands of big jumps and rough terrain.
- Non-Boost thru-axle: Before the introduction of Boost thru-axles, many mountain bikes used the non-Boost standards. The front axle is usually 100mm wide and either 15mm or 20mm in diameter, while the rear axle is 142mm wide and 12mm in diameter.
- Boost thru-axle: The Boost standards have become increasingly popular in recent years. The front axle is usually 110mm wide and either 15mm or 20mm in diameter, while the rear axle is 148mm wide and 12mm in diameter. These standards offer wider hubs, stronger wheels, and better clearance for tires and chainrings.
- Superboost thru-axle: The Superboost standards take things even further, providing even more stiffness, strength, and clearance than the Boost standards. The front axle is usually 110mm wide and either 15mm or 20mm in diameter, while the rear axle is 157mm wide and 12mm in diameter.
- Road bike thru-axle: With the rise of disc brakes on road bikes, thru-axles have also made their way into the road cycling world. The front axle is typically 100mm wide and 12mm in diameter, while the rear axle is 142mm wide and 12mm in diameter. These standards improve braking performance and consistency.
Thru Axle vs Quick Release: The Detailed Comparison
Stiffness and Stability
Quick answer: Thru axles win.
When it comes to the performance and handling of your bike, stiffness and stability play a crucial role. Let’s take a closer look at how thru axles and quick releases differ in these aspects.
To help you better understand how thru axles and quick releases affects the stiffness and stability of a bike, we are going to explain them from these aspects: lateral rigidity, torsional rigidity, and disc brake alignment.
Lateral rigidity: Lateral rigidity refers to the resistance of the wheel to bending or flexing sideways when subjected to lateral forces, such as cornering, crosswinds, or bumps. A higher lateral rigidity means a more responsive and accurate steering, as well as a better power transfer from the pedals to the wheels. A lower lateral rigidity means a more compliant and comfortable ride, but also a less precise and efficient handling. Thru axles generally provide more lateral rigidity than quick release skewers, as they have a larger diameter and a tighter fit with the frame or fork. This reduces the amount of movement and deformation of the wheel under lateral stress.
Torsional Rigidity: Torsional rigidity refers to the resistance of the wheel to twisting or rotating around its axis when subjected to torsional forces, such as braking, accelerating, or pedaling. A higher torsional rigidity means a more consistent and effective braking performance, as well as a better acceleration and deceleration. A lower torsional rigidity means a more flexible and forgiving ride, but also a less reliable and predictable braking performance. Thru axles generally provide more torsional rigidity than quick release skewers, as they have a longer length and a stronger connection with the frame or fork. This reduces the amount of rotation and distortion of the wheel under torsional stress.
Disc Brake Alignment: This refers to the alignment of the disc brake rotor with the brake caliper and pads when the wheel is attached to the bike. A good disc brake alignment means a smooth and quiet braking operation, as well as a longer lifespan of the brake components. A poor disc brake alignment means a noisy and inefficient braking operation, as well as a faster wear and tear of the brake components. Thru axles generally provide better disc brake alignment than quick release skewers, as they have a more precise and consistent positioning of the wheel in relation to the frame or fork. This reduces the amount of variation and misalignment of the disc brake rotor with the brake caliper and pads.
Security and Safety
Quick answer: The thru axle system takes the lead again.
Owing to its design and mechanism, it is stiffer, stronger, and more resistant to twisting forces compared to the quick release system. This means that the wheel is less likely to wobble or come loose during high-speed descents, sharp turns, or rough terrain.
Imagine you’re descending a steep mountain trail, filled with rocks and bumps. With a thru axle system, the wheel remains firmly attached to the frame and fork, preventing any unwanted movement or detachment that could lead to a crash or injury.
However, this does not cover all advantages that the thru axles can bring to riders in terms of security and safety. In the following, we will explain it with more details from the perspectives of wheel retention, theft prevention, and accident prevention.
Wheel Retention: Wheel retention refers to the ability of the wheel attachment to keep the wheel attached to the bike frame or fork under normal or extreme riding conditions. It is crucial for ensuring a safe and stable ride.
The quick release skewers, although widely used, are less reliable than thru axles in terms of wheel retention. They can loosen or open due to vibration, impact, or even human error. This can cause the wheel to detach from the bike unexpectedly, resulting in a loss of control and a possible crash.
To prevent this, bike owners need to regularly check and tighten their quick release skewers correctly. It’s also essential to ensure that they are closed and parallel to the bike frame when riding. Taking these precautions minimizes the risk of an accident caused by wheel detachment.
On the other hand, thru axles provide a more secure connection between the wheel and the frame or fork. They have a stronger and tighter grip, making them less likely to loosen or open due to external forces or human error. Thru axles also offer more precise and consistent positioning of the wheel in relation to the frame or fork, reducing the risk of misalignment or wobbling.
Theft Prevention: Speaking of theft prevention, thru axles also have the upper hand.
Quick release skewers are more vulnerable to theft as they can be easily opened and removed by hand, without the need for any tools. This means that thieves can steal the whole bike or just the wheel in a matter of seconds.
To prevent theft, bike owners using quick release skewers need to use additional locks or devices, such as cable locks, chain locks, or locking skewers, to secure their bikes or wheels.
Thru axles, on the other hand, are more resistant to theft. They require a specific tool, such as a hex key or a torque wrench, to loosen and remove them. Thieves would need the right tool and spend more time and effort to steal the bike or the wheel. To enhance theft prevention, bike owners can opt for anti-theft thru axles, such as Pitlock or Hexlox, which have unique keys or codes that only they can access.
Accident Prevention: In terms of accident prevention, thru axles offer a safer option compared to quick release skewers.
Quick release skewers have sharp and protruding parts that have the possibilities to cause injury to the rider or other road users in case of a collision or a fall. For example, a quick release lever can pierce through the skin or bone of a leg or an arm if it hits with enough force.
To prevent such injuries, bike owners need to be cautious and aware of their surroundings when riding, avoiding hitting or falling on their quick release skewers.
By comparison, thru axles have smooth and recessed parts that are less likely to cause injury in case of an accident. For example, a thru axle lever can be removed or folded into the axle when riding, making it less exposed and less harmful.
Ease of Use and Maintenance
Quick Answer: Quick release skewers win at this time.
Wheel Removal and Installation: As mentioned earlier, quick releases are designed for ease and speed. With a simple lever, you can open the skewer, loosen the nut, and pull out the axle. To install the wheel, you just need to insert the axle, tighten the nut, and close the lever. It’s a straightforward process that doesn’t require any additional tools.
Thru axles, on the other hand, require a bit more time and effort to remove and install the wheel. Depending on the type of thru axle, you may need to unscrew it from the frame or fork using a lever or an Allen key. Once removed, you’ll need to align the axle with the hub and screw it back in place, ensuring that it’s tight enough.
Adjustment and Alignment: Talking about the adjustment and alignment of your wheels, thru axles offer a more precise and consistent alignment, as they fit snugly into the frame or fork without any play or movement. This improved alignment can enhance the performance of your disc brakes, suspension forks, and rear derailleurs, as they are less likely to rub or misalign.
Quick releases, on the other hand, can have some variation in their alignment, depending on how tight or loose they are. This variation can affect the braking, shifting, and handling of your bike. However, you can adjust the tension of the quick release skewer by rotating the nut or the lever. It’s important to find the right balance, as a skewer that’s too tight can cause damage, while one that’s too loose can lead to wheel wobble.
So personally, I prefer the thru axles, even though they cost more time of mine.
Compatibility and Interchangeability: Even though we have mentioned earlier that both thru axles and quick release skewers have more than one standards for the bicycles, in terms of compatibility and interchangeability, quick releases win a little.
By comparison, the quick release system is more standardized and universal, with the same size and diameter for most bikes. This means that you can easily swap wheels or hubs with quick release skewers, as long as they have the same spacing and brake type.
Thru axles, however, are less compatible and interchangeable. They come in different sizes, lengths, diameters, threads, and shapes, depending on the brand and model of the bike. This means that you need to make sure you have the right type of thru axle for your frame or fork, as well as a compatible hub and wheel.
Weight and Aerodynamics
Quick Answer: Quick release skewers win again, but not significantly.
On average, a quick release skewer weighs around 20 grams less than a thru axle of similar quality. Quick release frames are also lighter because the dropouts contain less material. So, if you opt for quick release skewers instead of thru axles, you might save around 60-100 grams. However, it’s important to note that this weight difference is negligible in terms of speed and efficiency, unless you are racing at a very high level or climbing very steep hills. For most riders, the weight difference between thru axle and quick release is not a significant factor in their performance.
What about aerodynamics? Since thru axles are thicker and more exposed than quick release skewers, they potentially create more drag and reduce aerodynamics. However, there is no conclusive evidence or data to show how much this affects the speed and efficiency of the bike. Some studies have suggested that the shape and position of the spokes, rims, tires, and valves have a much greater impact on aerodynamics than the axles themselves. Therefore, the aerodynamic difference between thru axle and quick release is also not a significant factor in most cases.
Cost and Price
Quick Answer: Quick release skewers win, for sure.
Another important difference between thru axles and quick release skewers is the cost and price. Let’s take a closer look at the comparison.
In general, thru axles are more expensive than quick release skewers. This applies to both the axle itself and the frame and fork that are compatible with it. A single thru axle can cost between $30 and $60, depending on the brand and specifications. On the other hand, a pair of quick release skewers can cost just $10-$20 a set. So, if you’re on a budget or looking for a more affordable option, quick release skewers might be the way to go.
Different bicycle axles may also indicate that the whole bikes are with different price tags. Surely, the price of the frame and fork highly depend on the brand and model. However, in most cases, bikes with quick release systems tend to be more affordable compared to those with thru axles. So, if you’re looking to buy a new bike, opting for one with a quick release system might save you some money.
How to Choose Between Thru Axle and Quick Release
To choose between thru axles and quick release skewers, besides that the differences mentioned above can give you some hints, there are more factors which should come into your mind.
Here in this part, we will talk about two big ones: bicycle types and riding styles.
Different types of bikes may require or prefer different types of axles.
Mountain bikes, which are designed for riding on rough terrain and technical features, such as rocks, roots, jumps, drops, etc. usually prefer or require thru axles. This is because They need axles that are strong, durable, and stable, to prevent the wheel from wobbling or detaching during impacts. They also need axles that improve the alignment and performance of disc brakes, suspension forks, and rear derailleurs, which are essential for mountain biking. And these are just what the thru axles are good at.
On the other hand, road bikes are designed for riding on smooth pavement and achieving high speed and efficiency. They need axles that are light, aerodynamic, and comfortable, to reduce the weight and drag of the bike. They also need axles that optimize the stiffness and stability of the wheel, to improve handling and braking performance. Therefore, road bikes may prefer or require either thru axles or quick release skewers, depending on their preference and needs.
Gravel bikes, which are designed for mixed terrain, such as gravel roads, dirt paths, or paved roads, usually prefer or require thru axles. Thru axles provide versatility, reliability, and adaptability, making them suitable for different road conditions and situations. They also offer more strength and durability for the wheel, preventing wobbling or detachment during rough or hilly terrain.
Hybrid bikes, which are designed for general-purpose riding, such as commuting, recreation, or fitness, may prefer either thru axles or quick release skewers. This is because They need axles that are convenient, comfortable, and compatible, to suit different riding styles and preferences. They also need axles that work well with different types of brakes, such as rim brakes or disc brakes. Therefore, this type of bike, the axle choice highly depends on the preference and needs.
Road Racing: If you’re into road racing, speed, agility, and efficiency are key. The axle type can have a moderate impact on this style of riding. Thru axles are generally more suitable for road racing as they provide increased stiffness and stability for the wheel. This improves handling, braking, and suspension performance. Thru axles also enhance the alignment of disc brakes, which are increasingly popular on road bikes for their better modulation and power. On the other hand, quick releases may be less suitable for road racing as they are weaker and more prone to loosening or snapping during high-speed descents or sprints. Quick releases can also result in some misalignment of disc brakes, which could reduce your braking performance.
Mountain Biking: If you’re hitting the trails and tackling rough terrain, durability, traction, and control are crucial. In this case, the choice of axle type can have a significant impact on your riding experience. Thru axles are generally more suitable for mountain biking as they provide increased strength and durability for the wheel. This prevents wobbling or detachment during jumps, drops, or impacts. Thru axles also improve the performance of disc brakes, suspension forks, and rear derailleurs, as they are less likely to rub or misalign. On the other hand, quick releases are less suitable for mountain biking as they are thinner and more prone to bending or breaking during aggressive maneuvers. Quick releases can also compromise the performance of disc brakes, suspension forks, and rear derailleurs, as they allow for some variation in their alignment.
Commuting: If you’re using your bike for commuting purposes, convenience, comfort, and reliability are key. The choice of axle type may have a minor impact on this style of riding. Quick releases are generally more suitable for commuting as they allow for easy and fast removal and installation of the wheel without any tools. This can be useful for fixing a flat tire or other emergencies quickly, as well as for transporting or storing your bike easily. Quick releases also offer more compatibility and interchangeability with different wheels or hubs. On the other hand, thru axles may be less suitable for commuting as they require a tool (usually a hex wrench) to remove and install the wheel. This could be inconvenient for quick fixes or emergencies. Thru axles also have less compatibility and interchangeability with different wheels or hubs.
Touring: If you’re planning long-distance travel on your bike, touring requires a comfortable, reliable, and versatile setup. The choice of axle type can have a variable impact on this style of riding, depending on your preferences and the terrain you’ll encounter. For example, some touring riders may prefer thru axles for their increased performance and safety, especially for disc brake-equipped bikes. On the other hand, some touring riders may prefer quick releases for their convenience and compatibility, especially for rim brake-equipped bikes. Quick releases allow for easy and fast removal and installation of the wheel without any tools. This can be useful for fixing a flat tire or other emergencies quickly, as well as for transporting or storing your bike easily.
Can You Convert a Quick Release to a Thru Axle
It’s important to note that quick release and thru axle systems are not interchangeable. Each system requires a specific frame, fork, and hub design to work properly. Thru axle frames and forks have holes instead of slots for the dropouts, and thru axle hubs have larger diameter holes than quick release hubs. Quick release frames and forks have slots instead of holes for the dropouts, and quick release hubs have smaller diameter holes than thru axle hubs. Therefore, one cannot simply swap the axles without changing the other components as well.
However, there are exceptions, even though they are not common. Some wheel hubs can be converted to different axle types by changing the end caps, while others are fixed to one type. Similarly, some frames or forks have dropouts that can accept both quick release and thru axle, while others are designed for one type only.
To determine if your wheel hub and frame or fork are compatible with a thru axle, you can check the specifications of your components or measure the diameter and width of the axle and the dropout. Quick release axles are typically 9 mm or 10 mm in diameter and 100 mm or 135 mm in width, while thru axles can vary from 12 mm to 20 mm in diameter and from 100 mm to 197 mm in width.
When you get here, you have just finished all the contents. And we have helped you walk through what quick release skewers and thru axles are, how they differ from each other, how to choose between them, and whether a quick release can be converted into a thru axle.
Hopefully, you can learn something for this post, and finally understand and decide which type of axle is more suitable for your needs and preferences.