1. A Linked Or Combined Brake System:

A linked or combined brake system is a motorcycle braking setup that distributes braking force between the front and rear brakes, regardless of which brake lever or pedal the rider initially actuates. This system aims to simplify braking, enhance stability, and reduce the risk of wheel lockup, especially for less experienced riders.

Understanding Linked and Combined Brake Systems

While the terms "linked" and "combined" are often used interchangeably, there's a subtle difference. A linked brake system typically activates both front and rear brakes when either the front lever or rear pedal is applied. A combined brake system is more sophisticated, often using a proportioning valve or electronic control to distribute braking force optimally based on factors like speed, load, and deceleration. Both systems ultimately achieve the same goal: integrated braking for improved safety and control.

Why Were They Developed?

Motorcycle braking requires skill and coordination. Applying too much front brake can lead to a stoppie or front wheel lockup, while excessive rear brake can cause a skid. These situations are particularly dangerous for novice riders. Linked and combined brake systems were developed to:

• Simplify braking: Reduce the need for independent control of front and rear brakes.
• Enhance stability: Distribute braking force more evenly, minimizing the risk of skids and wheel lockup.
• Improve safety: Make braking more forgiving and less prone to rider error, especially in emergency situations.

How Linked and Combined Brake Systems Work

The core concept involves using a single control (either the front brake lever or the rear brake pedal) to activate both front and rear brakes to some degree. The specifics of how this is achieved vary depending on the system's design.

Mechanical Linkage

Early linked brake systems relied on mechanical linkages to connect the front and rear brake circuits. For instance, pressing the rear brake pedal might directly activate the rear brake and, through a series of levers and cables, also apply some pressure to the front brake. Similarly, pulling the front brake lever could activate both front calipers and a portion of the rear brake.

Advantages:

• Relatively simple and inexpensive to manufacture.
• Doesn't require complex electronics.

Disadvantages:

• Less precise control over brake force distribution.
• Can feel less natural to experienced riders accustomed to independent braking.
• Difficult to adjust and fine-tune.

Hydraulic Linkage with Proportioning Valves

A more advanced approach uses hydraulic pressure to link the brakes, often incorporating proportioning valves. These valves regulate the amount of pressure applied to each brake circuit based on factors like vehicle load and deceleration. For example, under heavy braking, the proportioning valve might allow more pressure to the front brake (where most of the stopping power resides) while limiting pressure to the rear to prevent lockup.

Advantages:

• More precise brake force distribution than mechanical linkages.
• Can be designed to provide a more natural braking feel.

Disadvantages:

• More complex and expensive than mechanical linkages.
• Requires careful calibration and maintenance.

Electronically Controlled Combined Brake Systems (eCBS)

Modern systems take advantage of electronic control to provide the most sophisticated and adaptable braking performance. An electronic control unit (ECU) monitors various parameters, such as wheel speed, throttle position, and brake lever/pedal pressure. Based on this data, the ECU precisely controls the amount of braking force applied to each wheel via hydraulic modulators.

Advantages:

• Highly precise and adaptable brake force distribution.
• Can integrate with other safety systems like ABS and traction control.
• Offers the most natural and confidence-inspiring braking feel.

Disadvantages:

• Most complex and expensive system to implement.
• Requires sophisticated electronic components and programming.

Examples of Linked/Combined Brake Systems

Several manufacturers have developed their own versions of linked or combined brake systems, each with its unique characteristics.

• Honda's Combined Braking System (CBS): Honda has been a pioneer in linked braking technology. Their CBS systems have evolved over the years, from simple mechanical linkages to sophisticated electronically controlled systems. Some versions of CBS are linked, where either front or rear brake application activates both brakes to a degree. Others are combined, using a proportioning valve to manage brake force distribution based on load and deceleration.

• BMW Motorrad Integral ABS: BMW's Integral ABS is an advanced combined braking system that integrates with their Anti-lock Braking System (ABS). It uses an electronic control unit to distribute braking force between the front and rear wheels, maximizing stopping power while minimizing the risk of wheel lockup.

• Brembo's Combined Braking Systems: Brembo, a leading manufacturer of motorcycle braking components, also offers combined braking systems. These systems often use hydraulic linkages and proportioning valves to optimize brake force distribution.

Benefits of Linked and Combined Brake Systems

• Enhanced Safety: By distributing braking force more effectively, these systems reduce the risk of wheel lockup and skids, especially in emergency braking situations.
• Improved Stability: The balanced braking force contributes to greater motorcycle stability, particularly when braking in corners or on uneven surfaces.
• Simplified Braking: Riders, especially beginners, find these systems easier to use because they don't have to precisely coordinate front and rear brake application.
• Reduced Rider Fatigue: The system assists with braking, which can reduce the physical and mental strain on the rider, especially during long rides.
• Increased Confidence: Knowing the system can help prevent loss of control during braking inspires greater rider confidence.

Potential Drawbacks

• Reduced Rider Input: Some experienced riders may find the linked or combined feel less natural and prefer the more direct control of independent brakes.
• Increased Complexity: Linked/combined systems, especially electronic ones, are more complex than traditional braking systems, potentially increasing maintenance costs.
• Potential for Malfunction: As with any complex system, there's a risk of malfunction, which could compromise braking performance.
• Added Weight: The additional components required for linked/combined systems can add weight to the motorcycle.
• Cost: Motorcycles equipped with these systems may be more expensive due to the additional technology.

The Science Behind It: How It Improves Braking

Linked and combined braking systems improve braking performance by addressing the physics of motorcycle braking. Here's a breakdown:

1. Weight Transfer: When braking, weight shifts forward onto the front wheel due to inertia. This increases the front tire's contact patch and its ability to generate braking force. A linked/combined system capitalizes on this by applying more braking force to the front wheel, where it's most effective.

2. Preventing Wheel Lockup: Wheel lockup occurs when the braking force exceeds the tire's grip. A locked wheel has significantly less traction than a rolling wheel, leading to a loss of control. Linked/combined systems prevent lockup by:

   • Distributing Force: Ensuring neither wheel is overloaded with braking force.
   • Proportioning Valves/Electronic Control: Precisely regulating brake pressure to each wheel based on available grip.

3. Optimizing Deceleration: By distributing braking force optimally, these systems maximize deceleration rates, allowing the motorcycle to stop in the shortest possible distance.

4. Enhancing Stability During Cornering: Linked/combined systems can be particularly beneficial when braking in corners. By applying a balanced braking force, they help maintain motorcycle stability and prevent the bike from standing up or running wide.

The Future of Motorcycle Braking

The future of motorcycle braking is likely to see even more sophisticated and integrated systems. Here are some trends to watch for:

• Advanced Rider Assistance Systems (ARAS): ARAS combines various safety technologies, including linked/combined braking, ABS, traction control, and radar-based systems, to provide comprehensive rider assistance.
• Cornering ABS: This advanced ABS system takes into account the motorcycle's lean angle when braking, further enhancing stability and preventing wheel lockup in corners.
• Predictive Braking Systems: These systems use sensors to detect potential hazards and automatically apply the brakes to mitigate or avoid collisions.
• Integration with Electric Motorcycles: As electric motorcycles become more prevalent, linked/combined braking systems will likely be integrated with regenerative braking systems to maximize energy recovery.

Maintaining a Linked or Combined Brake System

Maintaining a linked or combined brake system is crucial for ensuring its continued performance and safety. Regular maintenance tasks include:

• Brake Fluid Checks: Inspect the brake fluid level and condition regularly. Replace the brake fluid according to the manufacturer's recommendations (typically every one to two years) to prevent moisture contamination and corrosion.
• Brake Pad Inspection: Check the brake pad thickness regularly. Replace the pads when they reach the wear limit to maintain optimal braking performance.
• Brake Line Inspection: Inspect the brake lines for cracks, leaks, or damage. Replace any damaged lines immediately.
• Bleeding the Brakes: Bleed the brakes periodically to remove air bubbles from the system, which can compromise braking performance.
• System Calibration (for electronic systems): For electronically controlled systems, ensure the system is properly calibrated and functioning correctly. Consult a qualified technician for any necessary adjustments or repairs.
• Professional Servicing: For complex repairs or maintenance tasks, it's best to consult a qualified motorcycle technician who is familiar with linked/combined braking systems.

Are Linked/Combined Brakes Right for You?

The decision of whether or not to choose a motorcycle with linked or combined brakes depends on your individual needs and preferences. Consider the following factors:

• Riding Experience: Novice riders may benefit most from the added safety and ease of use of linked/combined brakes.
• Riding Style: Riders who prioritize maximum control and feedback may prefer independent brakes.
• Motorcycle Use: Riders who primarily commute or ride in urban environments may appreciate the added safety of linked/combined brakes.
• Budget: Motorcycles equipped with linked/combined brakes may be more expensive.

Conclusion

Linked and combined brake systems represent a significant advancement in motorcycle safety technology. By distributing braking force more effectively and simplifying the braking process, these systems can enhance stability, reduce the risk of wheel lockup, and improve overall rider confidence. While some experienced riders may prefer the direct control of independent brakes, linked/combined systems offer significant advantages for novice riders and those who prioritize safety and ease of use. As technology continues to evolve, we can expect even more sophisticated and integrated braking systems to emerge, further enhancing the safety and performance of motorcycles.

Frequently Asked Questions (FAQs)

Q: Are linked/combined brakes the same as ABS (Anti-lock Braking System)?

A: No, they are different but can work together. Linked/combined brakes distribute braking force, while ABS prevents wheel lockup. Many modern motorcycles combine both systems for maximum safety.

Q: Can I disable the linked/combined braking system on my motorcycle?

A: In some cases, it might be possible, but it's generally not recommended. Disabling the system could compromise braking performance and safety. Consult your motorcycle's owner's manual or a qualified technician for more information.

Q: Do linked/combined brakes make me a worse rider?

A: Not necessarily. While they assist with braking, they don't replace the need for good riding skills. It's still important to practice proper braking techniques and develop your skills.

Q: Are linked/combined brakes only for beginners?

A: No, riders of all skill levels can benefit from linked/combined brakes. They offer added safety and stability, which can be valuable in various riding situations.

Q: Are all linked/combined brake systems the same?

A: No, there are different types of linked/combined systems, ranging from simple mechanical linkages to sophisticated electronically controlled systems. The performance and feel can vary depending on the system's design.