TRP Hidden Brake Calipers Explained

In the pursuit of ultimate cycling performance, every detail counts. For time trial and triathlon cyclists, aerodynamics is not just a buzzword, it's a fundamental principle that dictates speed and efficiency. One area where significant gains can be made is in the braking system. Traditional brake calipers, while effective, can often disrupt the clean airflow around a bicycle frame. This is where the innovation of hidden brake calipers comes into play, and TRP (Tektro Racing Products) are at the forefront of this technology with their range of hidden brake calipers, particularly their offerings for specific framesets.

What are TRP Hidden Brake Calipers?

TRP hidden brake calipers are designed to be integrated discreetly into the bicycle frame, typically mounting underneath the chainstay or seatstay. This clever placement minimises their exposure to the wind, thereby reducing aerodynamic drag. The primary benefit of this design is a smoother, cleaner airflow over the frame, which can translate into tangible speed advantages, especially at higher speeds experienced in racing scenarios.

The TRP hidden brake calipers, specifically mentioned for the ARC-TT frameset, exemplify this design philosophy. They boast a super aerodynamic design, a crucial factor for any component intended for time trial or triathlon use. Constructed from forged and CNC’d aluminium arms, these calipers offer a blend of strength, light weight, and precision engineering. The use of high-quality materials ensures durability and reliable stopping power, even under demanding race conditions.

Key features of these specific TRP hidden calipers include:

• Mounting: They are designed to mount under the chain stay or seat stay on integrated brake posts. This means the frame needs to be specifically designed to accommodate this type of caliper, ensuring a flush and aerodynamic fit.
• Adjustability: Individual spring tension screws allow for precise adjustment of the brake return spring. This enables riders to fine-tune the brake feel and ensure the calipers retract cleanly after braking, further enhancing aerodynamics.
• Maintenance: They utilise standard, replaceable cartridge brake pads. This is a significant advantage for maintenance and servicing, as readily available cartridge pads are easy to swap out, ensuring consistent braking performance and reducing downtime.
• Weight: The weight is impressively low, with a figure of 134g per wheel including the noodle, pads, and all necessary hardware. This low weight contributes to the overall efficiency of the bicycle.

Understanding Brake Pull Ratios: TRP V-Brakes

While the initial focus is on hidden calipers, the provided information also delves into the specifics of TRP V-brakes, particularly their pull ratios. Brake pull ratio is a critical specification that determines how much the brake pads move for a given amount of cable pulled by the brake lever. Different brake levers and brake calipers are designed to work optimally with specific pull ratios. Mismatching them can lead to either insufficient braking power or an excessively long and spongy lever feel.

TRP offers different versions of their TTV brake, each with a distinct pull ratio suited for different applications:

TRP TTV (Aero)

The TRP-TTV06-F-K (front) and TRP-TTV09-R-K (rear) are designated as 'Aero' brakes. These are likely designed for TT/Triathlon bikes where the braking is often integrated into the aero bars or frame, and the lever pull is designed to be minimal and very direct.

Specifications for the TRP TTV (Aero) include:

• Pivot bolt to brake pad distance: 24.5mm +/-4.5mm. This measurement influences the leverage applied.
• Pivot bolt to cable fitting: 65mm. This distance is crucial for calculating the mechanical advantage.
• C-C width of pivot bolts: 61mm +/- 1.5mm (for 19-25mm tyres). This refers to the distance between the two mounting bolts, important for frame compatibility.
• Frame/Fork Suitability: Suited for an axle to centre of pivot bolt fork/frame of 284mm. This indicates the required frame geometry for optimal mounting.
• Leverage Pull Ratio:2.6. This is a high leverage ratio, meaning it requires less cable pull from the lever to move the brake arms a significant amount. This is often paired with specific aero brake levers that have a short cable pull.

TRP TTV RD (Road)

The TRP-TTV-ROAD-F (front) and TRP-TTV-ROAD-R (rear) are designed for standard road use. These often feature a more conventional caliper mounting position, though they can still be designed for aerodynamic benefits.

Specifications for the TRP TTV RD (Road) include:

• Pivot bolt to brake pad distance: 44mm +/-7mm. This is a larger distance than the aero version, contributing to a different leverage characteristic.
• Pivot bolt to cable fitting: 78mm.
• C-C width of pivot bolts: 58mm +/- 1.5mm (for 21-28mm tyres). This range accommodates slightly wider road tyres.
• Frame/Fork Suitability: Suited for an axle to centre of pivot bolt fork/frame of 268mm.
• Leverage Pull Ratio:1.8. This is a standard road pull ratio, designed to work with the majority of standard road brake levers.

TRP TTV (OEM)

These TRP TTV brakes are supplied as Original Equipment Manufacturer (OEM) components to major bike brands like Argon, BMC, and Scott. They are not typically available directly from aftermarket suppliers like Upgrade. If you have a bike with these brakes, you would need to contact the bike frame supplier for replacements or parts.

Key characteristics of the OEM version:

• Mounting Pin: The locating spring pin is positioned at the top of the frame/fork mount.
• Pivot bolt to brake pad distance: 42mm front and 43mm rear.
• Pivot bolt to cable fitting: 76mm.
• C-C width of pivot bolts: 55mm +/- 1mm front, 61mm +/- 1mm rear.
• Frame/Fork Suitability: Suited for an axle to centre of pivot bolt fork/frame of 266mm.
• Leverage Pull Ratio:1.8. This indicates they are designed for standard road pull levers.

Are TRP Hidden Brake Calipers Right for You?

The decision to switch to TRP hidden brake calipers, particularly those designed for specific frames like the ARC-TT, hinges on several factors. Firstly, your existing frameset must be compatible. These calipers are not a universal fit; they require integrated brake posts designed to accommodate their unique mounting position. If you ride a modern time trial or triathlon bike, there's a good chance it's designed with hidden brake mounting points.

Secondly, consider your primary cycling discipline. If you are a serious competitor in time trials or triathlons, the aerodynamic benefits can be significant. Even small reductions in drag can add up over the duration of a race, potentially shaving valuable seconds or minutes off your finish time. The precise engineering and high-quality materials used by TRP ensure that these aerodynamic gains do not come at the expense of braking performance or reliability.

For road cyclists, while aerodynamic improvements are always welcome, the benefits of hidden calipers might be less pronounced compared to the more direct impact seen in TT/Triathlon. However, TRP also offers road-specific variants (like the TTV RD) that can still offer a cleaner look and potentially improved aerodynamics over some traditional brake designs, while ensuring compatibility with standard road brake levers thanks to their 1.8 pull ratio.

Compatibility: Levers and Calipers

The most crucial aspect of upgrading or replacing brake components is ensuring compatibility between your brake levers and your brake calipers. As highlighted by the different pull ratios (2.6 for aero TTV, 1.8 for road TTV), TRP has catered to different systems. If you have aero brake levers with a short cable pull, you'll likely need calipers with a higher leverage ratio (like the aero TTV) to achieve optimal braking. Conversely, if you're using standard road brake levers, which typically pull more cable, you'll need calipers with a lower leverage ratio (like the road TTV or OEM versions) to match.

Using the wrong combination can lead to:

• Too little braking power: If your lever pulls a lot of cable, but your caliper has a high leverage ratio (low cable pull requirement), the pads won't move far enough to engage the rim effectively.
• Spongy or weak lever feel: If your lever pulls very little cable, but your caliper has a low leverage ratio (high cable pull requirement), you'll need to pull the lever a lot, and the braking might feel weak or the lever might hit the handlebar before achieving sufficient stopping power.

Always consult the specifications of both your brake levers and your chosen TRP calipers to ensure they are designed to work together. If in doubt, seeking advice from a qualified bike mechanic is highly recommended.

Maintenance and Care

TRP hidden brake calipers, particularly those with cartridge brake pads, are designed with user-friendliness in mind. The ability to easily replace cartridge pads is a significant advantage. When the brake pads wear down, you simply unclip the old ones and clip in new ones. This is a much simpler and quicker process than replacing traditional brake shoes.

Regular cleaning of the brake track on your wheel rims is essential for optimal braking performance. Ensure that the brake pads are free from debris, grit, or metallic fragments, which can damage the rim and reduce braking efficiency. Periodically check the brake cable and housing for any signs of wear or damage, and ensure the spring tension screws are secure and correctly set.

For hidden calipers, access can sometimes be more challenging than with standard calipers. It's important to keep the mounting area clean and free from corrosion. If your bike is used in wet or dirty conditions, giving these areas a regular clean and perhaps a light lubrication can prevent issues down the line.

Frequently Asked Questions (FAQs)

Q1: Can I fit TRP hidden brake calipers to any bike?
No, TRP hidden brake calipers are typically designed for frames that have specific integrated brake mounting points. They are not a universal replacement for standard brake calipers.

Q2: What is the main advantage of hidden brake calipers?
The primary advantage is improved aerodynamics due to reduced wind resistance. They offer a cleaner, smoother airflow around the frame.

Q3: How do I know which TRP TTV pull ratio I need?
You need to match the pull ratio of the caliper to the pull ratio of your brake levers. The TRP TTV Aero has a 2.6 ratio (for short-pull aero levers), while the TRP TTV RD and OEM versions have a 1.8 ratio (for standard road levers).

Q4: Are TRP brakes good quality?
TRP (Tektro Racing Products) is known for producing high-quality, reliable components, often offering excellent performance at a competitive price point. Their brakes are widely used in professional cycling.

Q5: How do I maintain TRP hidden brake calipers?
Maintain them by regularly cleaning the brake pads and rim track, replacing cartridge pads when worn, and keeping the mounting area clean and free of debris.

In conclusion, TRP hidden brake calipers represent a sophisticated solution for cyclists seeking to optimise their aerodynamic performance. Whether you're a time trial specialist or a triathlete aiming for a personal best, these components offer a blend of cutting-edge design, quality materials, and functional excellence. Understanding the nuances of brake pull ratios and ensuring frame compatibility are key to unlocking the full potential of these advanced braking systems.