Mechanical vs Hydraulic Disc Brakes: Which One is Best for Your Bike

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Disc brakes have become increasingly popular in the cycling world due to their superior stopping power and reliability, especially in wet and muddy conditions. If you’re considering upgrading to disc brakes or purchasing a new bike with disc brakes, you might be wondering which type is best for you: mechanical or hydraulic.

In this article, we’ll compare and contrast mechanical and hydraulic disc brakes to help you make an informed decision. We’ll look at their performance, maintenance requirements, cost, and compatibility with different bike setups. So let’s dive in and explore the differences between these two types of disc brakes.

Mechanical vs Hydraulic Disc Brakes: Performance

Speaking of the performance of a braking system, we would usually like to talk about it in three more detailed ways, its braking power, modulation, and consistency.

So how about mechanical disc brakes and hydraulic disc brakes?

1. Braking Power

Having a better braking power on your bicycle is particularly important, and you can deal with various cycling situations with ease, such as:

Downhill Riding: When descending steep hills, you need brakes that can provide enough stopping power to control your speed and navigate tight corners.

Wet Conditions: Riding in wet or rainy conditions can significantly reduce the effectiveness of your brakes.

Emergency Stops: In emergency situations where you need to stop quickly, having brakes with ample stopping power is crucial.

Etc.

So which one has better braking power, the mechanical disc brake or the hydraulic disc brake?

Hydraulic disc brakes have more braking power than mechanical disc brakes.

This is because they can apply more force with less effort. Hydraulic disc brakes work by using a sealed fluid system that transfers the braking force from the lever to the caliper. The fluid is incompressible, meaning it does not change its volume when pressure is applied. This means that the force you apply to the lever is transmitted directly to the brake pads, without any loss or delay. As a result, hydraulic disc brakes offer more stopping power and can bring you to a halt faster and more efficiently.

On the other hand, mechanical disc brakes work by using a steel cable that connects the lever to the caliper. The cable is flexible and can stretch, bend, or fray over time. This means that some of the force you apply to the lever is lost or reduced along the way, and you need to pull harder to achieve the same braking effect. While mechanical disc brakes still provide adequate stopping power for most situations, they may not be as powerful as hydraulic disc brakes, especially in demanding conditions or for riders who require maximum stopping power.

2. Modulation

Braking power is the ability of the brakes to decelerate your bike. It’s measured by the force applied to the brake lever and the resulting force applied to the wheel. The more force you can apply, the faster you can stop. However, too much braking force can lead to skidding and loss of control, especially on slippery surfaces.

So, it’s important to have a brake system that allows you to control the amount of braking force applied.

That’s where modulation comes into play. Modulation is the ability to control the amount of braking force applied to the wheel, and how smoothly and precisely you can do that. It’s important for braking performance, as it allows you to avoid locking up the wheels and skidding, and also to adjust your speed and balance according to the terrain and conditions, such as: cornering: When taking a sharp turn, you need to modulate your braking force to maintain control and prevent skidding, or riding in traffic: In busy urban environments, you often need to brake quickly and precisely to avoid collisions, etc.

Now let’s compare mechanical and hydraulic disc brakes in terms of modulation.

Hydraulic disc brakes have better modulation than mechanical disc brakes.

Why?

Because mechanical disc brakes use a cable that can stretch, fray, or get contaminated by dirt or water,  to transfer the braking force from the lever to the caliper. Cable tension can also vary depending on how well the cable is routed, how tight the housing is, and how often the cable is lubricated. Mechanical disc brakes also require manual adjustment of the brake pads as they wear down, which can affect the lever feel and travel. As a result, mechanical disc brakes have a more vague and inconsistent feel, and you need to apply more force and finesse to modulate them.

On the other hand, hydraulic disc brakes have a smoother and more responsive feel. They use fluid pressure to transfer the braking force from the lever to the caliper, instead of a steel cable. This fluid pressure is more consistent and responsive than cable tension, as it does not suffer from friction, stretch, or slack.

In addition, hydraulic disc brakes have a self-adjusting mechanism that keeps the brake pads at a constant distance from the rotor, regardless of wear or temperature changes. This means that hydraulic disc brakes have a more predictable and linear feel, and you can modulate them with less effort and more accuracy.

3. Consistency

When we are talking about the consistency of a braking system, it is the ability to maintain the same level of braking performance over time and in different conditions. And for these two braking systems, hydraulic disc brakes tend to have more consistent performance compared to their mechanical counterparts.

Why is that? There are three major reasons:

1. Cable Stretch: Mechanical disc brakes use a steel cable to connect the brake lever to the brake caliper. Over time, this cable can stretch due to wear and tear, which can reduce the braking force and require frequent adjustments. On the other hand, hydraulic disc brakes use a sealed fluid system to transfer the braking force from the lever to the caliper. There is no cable involved, so there is no risk of cable stretch or loss of tension.

2. Dirt: Mechanical disc brakes are more exposed to dirt and debris that can contaminate the cable and housing, causing friction and reducing performance. Hydraulic disc brakes, on the other hand, are less affected by dirt because the fluid system is sealed and protected from external elements. The fluid also acts as a lubricant, reducing friction and improving performance.

3. Temperature Changes: Mechanical disc brakes can be affected by temperature changes, which can cause the cable to contract or expand, altering the braking force and modulation. Hydraulic disc brakes, on the other hand, are more resistant to temperature changes because the fluid system is self-adjusting and compensates for any expansion or contraction of the fluid volume. This means that hydraulic disc brakes provide consistent performance regardless of temperature fluctuations.

Consistency becomes particularly important in certain situations, such as long rides, changing weather conditions, or varying terrain. Imagine you’re on a long-distance ride, and you need reliable braking power throughout the journey. Hydraulic disc brakes will provide consistent performance, ensuring your safety and control, even as you clock in the miles.

Similarly, if you’re riding in changing weather conditions, such as rain or snow, consistent braking performance becomes crucial. Hydraulic disc brakes, with their sealed system, are less affected by moisture and can provide reliable stopping power in wet conditions.

Lastly, when tackling varying terrains, such as steep descents or technical trails, having brakes that offer consistent performance is essential. Hydraulic disc brakes excel in maintaining their braking power and modulation, regardless of the terrain, allowing you to confidently navigate challenging routes.

Mechanical vs Hydraulic Disc Brakes: Maintenance

Both mechanical disc brakes and hydraulic disc brakes require regular maintenance to ensure they are working properly and safely, but the frequency and complexity of that maintenance can vary.

Mechanical disc brakes, as the name suggests, rely on mechanical cables to actuate the brake calipers. These cables can stretch over time, causing the brake pads to move further from the rotor and reducing braking performance. As a result, mechanical disc brakes require more frequent adjustments to compensate for cable stretch, pad wear, and rotor alignment.

mechanical disc brake

One of the main reasons mechanical disc brakes require more frequent maintenance is that they are exposed to the elements. This exposure can lead to cable stretch, fraying, or rusting, which affects the overall performance of the brakes. Additionally, mechanical disc brakes need manual adjustment to keep the brake pads aligned with the rotor and prevent rubbing or squeaking noises.

On the other hand, hydraulic disc brakes use brake fluid to transmit the force from the lever to the caliper, where the brake pads squeeze the rotor and slow down the bike. Unlike mechanical disc brakes, hydraulic systems have sealed systems that prevent contamination from dirt, water, or air.

The use of brake fluid in hydraulic disc brakes allows for self-adjustment. Brake fluid has a property called compressibility, which means it can change its volume slightly under pressure. This allows the brake pads to move closer or farther from the rotor depending on the force applied to the lever. As a result, hydraulic disc brakes automatically compensate for brake pad wear and maintain a consistent braking feel.

Hydraulic disc brakes are generally more reliable, powerful, and consistent in different weather conditions and terrain types. Their sealed systems protect the brake fluid from contamination, reducing the need for frequent maintenance.

To give you a better idea of the maintenance frequency for each type of brake, here are some examples:

Mechanical Disc Brakes:

  • Cable tension adjustment: Every few weeks or when necessary
  • Pad clearance adjustment: Every few weeks or when necessary
  • Rotor alignment: Every few weeks or when necessary

Hydraulic Disc Brakes:

  • Brake fluid check: Every few months or when necessary
  • Bleeding the system: Every 6-12 months or when necessary
  • Replacing seals: Every 1-2 years or when necessary

Next, in terms of maintenance difficulty, mechanical disc brakes are generally easier to maintain than hydraulic disc brakes. Mechanical systems have simpler components and can be adjusted with basic tools and skills. Adjusting cable tension, pad clearance, and rotor alignment can be done by most riders with some basic knowledge.

On the other hand, hydraulic disc brakes have more complex components and require specialized tools and skills for maintenance. Bleeding the system, replacing seals, and other hydraulic maintenance tasks are best left to experienced mechanics or riders with advanced knowledge.

Mechanical vs Hydraulic Disc Brakes: Cost

When choosing the right disc brakes for your bike, cost is an important factor to consider. First, you need to know that the cost of disc brakes is not just about the initial purchase price, but also the replacement parts price and the service fee. Here, we will compare mechanical disc brakes and hydraulic disc brakes in terms of cost to help you make an informed decision.

Mechanical disc brakes are generally cheaper than hydraulic disc brakes. This is because mechanical disc brakes have fewer parts and are made with relatively lower quality materials. On the other hand, hydraulic disc brakes have more parts and are made with higher quality materials, making them more expensive.

To give you an idea of the price range, mechanical disc brakes typically cost between $50 and $100. On the other hand, hydraulic disc brakes can range from $100 to $300. These prices can vary depending on the brand and model.

When it comes to replacement parts, mechanical disc brakes have the advantage of using standard cables, housing, pads, and rotors. This means that the replacement parts for mechanical disc brakes are generally cheaper compared to hydraulic disc brakes.

For example, a cable for mechanical disc brakes can cost anywhere from $5 to $10, while a pad can range from $10 to $20. On the other hand, hydraulic disc brakes require specific fluid, hoses, pistons, pads, and rotors. As a result, the replacement parts for hydraulic disc brakes are more expensive. For example, a hose for hydraulic disc brakes can cost between $10 and $20, while a piston can range from $20 to $40. Again, these prices can vary depending on the brand and model.

In terms of service fees, mechanical disc brakes generally have lower costs compared to hydraulic disc brakes. This is because mechanical disc brakes can be serviced by most bike shops or even DIY enthusiasts. On the other hand, hydraulic disc brakes require specialized equipment and expertise, which can drive up the service fees.

Mechanical vs Hydraulic Disc Brakes: Compatibility

1. Frame and Fork

You must know that different bikes have different mounts and cable or hose routing options, and it’s essential to ensure that the disc brake system you choose is compatible with your bike’s design.

Mechanical disc brakes are generally more compatible with most frames and forks because they use standard mounts and cable routing. These brakes rely on a cable mechanism to activate the calipers, which means they can easily work with various frame and fork designs. Whether your bike has internal or external cable routing, mechanical disc brakes can usually be installed without any issues.

On the other hand, hydraulic disc brakes are less compatible with some frames and forks due to their specific mounts and hose routing requirements. Hydraulic brakes use fluid pressure to engage the calipers, which can result in different mounting standards and hose routing options. While many modern frames and forks are designed to accommodate hydraulic disc brakes, older or specialized frames may not have the necessary mounts or routing options.

How to Check

To determine whether mechanical or hydraulic disc brakes are compatible with your frame and fork, here are a few things to consider:

1. Mount Types: Look for the International Standard (IS), Post Mount (PM), or Flat Mount (FM) types. These are the most common disc brake mount standards, and you need to ensure that your frame and fork have the corresponding mounts for your chosen brake system.

2. Cable or Hose Routing: Check whether your bike has internal or external cable or hose guides. Mechanical disc brakes typically use external cable routing, while hydraulic disc brakes may require internal hose routing. Make sure your frame and fork have the necessary guides to accommodate your chosen brake system.

3. Frame and Fork Compatibility Charts: Some brake manufacturers provide compatibility charts that list compatible frames and forks for their disc brake systems. Consult these charts to ensure that your bike is compatible with the brakes you want to install.

It’s worth noting that while mechanical disc brakes are generally more compatible, hydraulic disc brakes offer superior performance and modulation. If you have a bike with specialized frame requirements or are willing to invest in frame modifications, hydraulic disc brakes can be a great option.

2. Wheel

Before diving into the specifics of disc brake compatibility with wheels, it’s important to understand how wheel design can affect compatibility. There are two key aspects of wheel design that play a role in disc brake compatibility: the type of rotor attachment and the type of hub.

Rotor Attachment Types:

  • 6-Bolt: This is the most common type of rotor attachment and is characterized by six evenly spaced bolt holes on the rotor. It’s important to note that some manufacturers use a slightly different bolt pattern, so it’s always a good idea to check the specifications.
  • Centerlock: This type of rotor attachment features a splined interface that allows the rotor to be quickly and securely attached to the hub using a lockring. Centerlock rotors are becoming increasingly popular due to their ease of installation and removal.
  • Splined: Some disc brake systems, particularly those designed for mountain biking, use splined rotors that slide onto a corresponding splined interface on the hub. This design offers a secure and precise attachment.

Hub Types:

  • Quick Release (QR): This is the traditional hub design that uses a quick-release skewer to attach the wheel to the frame or fork. QR hubs have a 100mm width for front wheels and 135mm width for rear wheels.
  • Thru-Axle (TA): Thru-axles have become more common in recent years, particularly in off-road disciplines. They offer increased stiffness and stability compared to quick-release systems. TA hubs come in different widths, such as 12mm or 15mm for mountain bikes and 12mm for road bikes.
  • Boost: Boost hubs have wider spacing, with 110mm for the front wheel and 148mm for the rear wheel. This wider spacing allows for increased tire clearance and improved wheel stiffness.

Mechanical disc brakes are known for their simplicity and reliability. One of the advantages of mechanical disc brakes is their compatibility with a wide range of wheels. This is because mechanical disc brakes use standard rotors and hubs that are compatible with most bike frames and forks.

For example, if your bike has a 6-bolt rotor attachment, you can easily find mechanical disc brakes that are compatible with this type of rotor. Similarly, mechanical disc brakes can be used with both QR and TA hubs, as long as the rotor size matches the hub width.

Hydraulic disc brakes offer superior braking performance and modulation compared to mechanical disc brakes. However, their compatibility can be more limited due to the specific rotor and hub requirements.

hydraulic disc brake

Hydraulic disc brakes often use specific rotors and hubs that are designed to work together for optimal performance. This means that if your bike has a centerlock rotor attachment, you’ll need to choose hydraulic disc brakes that are compatible with centerlock rotors. The same applies to splined rotor attachments.

Additionally, hydraulic disc brakes may have specific requirements for hub spacing. For example, if you have a Boost hub, you’ll need to ensure that the hydraulic disc brakes you choose are compatible with this wider hub spacing.

How to Check

To check the compatibility of disc brakes with your wheels, you can look for the following:

  1. Rotor Attachment: Determine whether your wheels have a 6-bolt, centerlock, or splined rotor attachment. This will help you choose the appropriate disc brakes.
  2. Hub Type: Identify whether your wheels use a QR, TA, or Boost hub. This will ensure that the disc brakes you choose are compatible with your hub spacing.

It’s worth noting that some disc brake manufacturers offer adapters or conversion kits that allow you to use different rotor attachment types or hub widths. These can be useful if you want to switch between different disc brake systems or if you have a wheelset with a different hub spacing.

3. Shifter

The design of your bike’s shifters determines how the brake lever interacts with the brake caliper. Mechanical and hydraulic disc brakes have different mechanisms for transferring force from the brake lever to the caliper, and this can affect compatibility.

Mechanical disc brakes are generally more compatible with most shifters because they use standard cable pull ratios. Cable pull ratio refers to the amount of cable that needs to be pulled to engage the brake caliper. Mechanical disc brakes have a consistent cable pull ratio across different brands and models, making them easier to pair with a wide range of shifters.

For example, if you have a road bike with Shimano shifters, you can confidently choose mechanical disc brakes from various brands, knowing that they will be compatible. The same goes for mountain bike or hybrid bike setups. The standard cable pull ratio ensures a smooth and reliable braking experience.

On the other hand, hydraulic disc brakes are less compatible with some shifters because they use specific fluid volumes to transfer force. Different brake systems may have different fluid volumes, which can lead to compatibility issues when pairing hydraulic disc brakes with certain shifters.

For instance, if you have a road bike with SRAM shifters, you might encounter compatibility challenges when selecting hydraulic disc brakes from different brands. The fluid volume required by the brake system may not match the volume supported by the shifter. This can result in inconsistent brake performance or even complete incompatibility.

How to Check

To check the compatibility of your disc brakes with your shifters, there are a few key factors to consider:

1. Cable Pull Ratios: For mechanical disc brakes, look for road, mountain bike, or hybrid cable pull ratios that match your shifter’s specifications. This ensures that the brake caliper will respond properly to the movement of the brake lever.

2. Fluid Volumes: For hydraulic disc brakes, pay attention to the fluid volume requirements specified by the brake manufacturer. Match these requirements with the fluid volume supported by your shifter to ensure compatibility. Some common hydraulic disc brake brands include Shimano, SRAM, and Magura, each with their own specific fluid volume requirements.

3. Research and Consultation: If you’re unsure about the compatibility between your shifters and disc brakes, do some research or consult with a bike mechanic or knowledgeable cycling community. They can provide valuable insights and recommendations based on their experience and expertise.

Cable-Actuated Hydraulic Disc Brakes: Are They the Solution?

Cable-actuated hydraulic disc brakes are a hybrid type of disc brakes that use a cable to activate a hydraulic system at the caliper. They are designed to provide the benefits of both mechanical and hydraulic disc brakes, offering the power and modulation of hydraulic brakes with the simplified maintenance of mechanical brakes.

cable-actuated hydraulic disc brake

The cable-actuated hydraulic disc brake system consists of a lever, cable, housing, caliper, and rotor. When you pull the brake lever, the cable is engaged and pulls on a piston in the lever. This piston pushes hydraulic fluid through the hose and into the caliper, where it activates the brake pads to squeeze the rotor, resulting in braking power.

With the improvements and changes in designs, cable-actuated hydraulic disc brakes offer excellent braking power and modulation. They provide more stopping power than mechanical disc brakes, making them a great choice for riders who want hydraulic disc brakes and need precise control over their braking, but not as good as the genuine hydraulic disc brakes.

Another one of the biggest advantages of cable-actuated hydraulic disc brakes is their simplified maintenance. Unlike traditional hydraulic disc brakes, cable-actuated hydraulic brakes do not require bleeding or fluid replacement. This means less time spent on maintenance and more time riding, but not as easy as maintaining the mechanical disc brakes.

Besides, cable-actuated hydraulic disc brakes are generally more affordable than full hydraulic disc brakes. They have fewer parts and lower-quality materials in the lever and hose, making them a cost-effective option for riders on a budget, but not as cheap as the mechanical disc brakes.

So you can basically take the cable-actuated hydraulic disc brakes as a non perfect upgrade of the hydraulic disc brakes. They can give you some benefits that the pure hydraulic disc brakes do not have, but at the same time also lose some portion of the benefits that the pure hydraulic disc brakes have.

Conclusion

When you get here, you must have had some knowledge of how the mechanical disc brakes and the hydraulic disc brakes differ from each other, in the fields of performance, maintenance, cost, and compatibility.

So by far which one do you prefer? You are welcomed to share your opinions, experiences, or questions about mechanical and hydraulic disc brakes in the comments section below.

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AUTHOR

Randy Joycelyn

Randy is the founder and editor of Cycling Soigneur. He has been passionate about cycling since he was a kid. He has been riding bikes for over 10 years. Cycling has just become a part of life.

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