Replacement Rotors for Paragon Alcon Mono4 355mm Big Brake Kit - Rear Pair

These rotor rings (friction rings) are direct replacement for Paragon Alcon Mono4 355mm rear brake kit. Sold in pairs.

Comes with new rotor attachment hardware kits (enough for 2 rotors) and assembly instructions for a complete rebuild.

Paragon Performance Rotor Ring offers superior braking and cooling efficiency optimized for track and race applications. It features directional ventilation vanes to create suction, turbulence, and guides cool air through the rotor for improved heat dissipation and increased resistance to cracking under harsh track condition.

Made of CM-250 special formulated high carbon alloy cast iron, it allows for an optimal bite, thermal characteristics, high-temperature strength and durability. Rotor rings are heat treated to release stress in the rotor to avoid deformation and vibration then turned by state-of-the-art CBN surface machining to ensure better break-in with new brake pads.

Vibration is reduced as the rotor lateral run-out is kept within 0.03mm and well-balanced: variations are kept within 2 grams. All rotor rings went through rigorous quality control procedures and inspections to ensure the rotor rings are fit for their purposes. 2-piece design allows thermal expansion of the rotor while minimizing deformation and ensuring the rotor is self-centered with the pads. A slotted rotor improves braking consistency by maintaining a clean contact surface and dissipate heat generated and gases released when the pads come into contact with the rotors. Slotted rotors have a superior advantage over blank rotors in wet or raining conditions by preventing water films to form between the brake pad and rotor surface. Weighing less than most O.E. rotors while maintaining proper thermal capacity, our rotors improves overall handling by saving unsprung mass.

Directional ventilation vanes for optimal cooling performance and increased resistance to cracking. Run up to 30% cooler than O.E. rotors and increase cooling efficiency by up to 30%
2-piece design
Minimizing brake fade & judder during extended sessions

Part Number: PRK.51.355.320.23500.03.01.R

Please refer to our Rotor Assembly Instructions for torque specs and detailed instructions.

Wheel Fitment

> How to use the wheel fitment template (PDF)

SKU: PRK.51.355.320.23500.03.01.R

Best For: Enthusiast Drivers Who Want Fitment Confidence and Consistent Braking

These rotors are best for drivers who care about correct fitment, predictable pedal feel, and repeatable braking performance under real use. They suit enthusiast street cars and dual-purpose builds where braking consistency matters more than generic catalog parts.

FAQ

Do these fit the factory rotor hats?
These rotor rings fit Paragon hats, or the original equipment hats when the vehicle came with a factory 2-piece rotor design. If your application uses a 1-piece factory rotor, these are not intended to bolt to an OE hat because there is no separate hat to reuse.

Are these complete rotors or replacement rings?
These are replacement rotor rings only. They are designed to service the braking surface while reusing the existing hat when the hat is compatible.

Do slotted rotors improve braking?
Slots primarily improve pad cleaning and help maintain consistent braking feel under heat. They do not create a dramatic change in stopping distance by themselves, but they can help the system stay more consistent during repeated hard stops.

When should rotor rings be replaced?
A practical wear indicator is slot depth. When the slots become shallow and much less visible, the rotor is typically nearing the end of its effective service life. Rotor thickness, heat checking, cracking, and brake vibration should also be inspected during service.

Should I replace pads at the same time?
Yes, in most cases. Fresh pads help the new rotor surface bed in correctly and reduce the chance of uneven deposits, noise, or inconsistent pedal feel.

Brake Rotor Technology

Why high-carbon rotors matter
High-carbon cast iron offers better thermal stability than generic low-cost rotor materials. That helps the rotor maintain more consistent behavior as temperature rises, which is important on heavier vehicles and on cars driven aggressively.

Directional vane cooling
Directional internal vanes are designed to move air through the rotor more effectively, improving heat evacuation and helping the rotor recover more quickly between braking events.

Slotted rotor surface
Slots help keep the pad face clean by clearing away gases, dust, and debris. The result is more consistent pad contact and more repeatable braking feel, especially when the system is worked hard.

When to Replace Rotor Rings

Rotor rings should be replaced when the friction surface shows meaningful wear, heat fatigue, or thickness loss. One of the easiest visual indicators is the depth of the rotor slots. As the rotor wears, the slots become shallower. When they are much less visible, the rotor is generally nearing the end of its useful service life.

Other common signs include visible heat checking or cracking, brake pulsation, heavy scoring, and rotor thickness approaching the service limit.

Why Replace Rotor Rings Instead of the Whole Rotor?

On vehicles that use 2-piece rotors, the friction ring can be replaced independently from the hat. That allows the wear component to be serviced without replacing the full assembly, which can reduce replacement cost while preserving the benefits of the 2-piece design.

Common Mistakes When Replacing Rotors

Reusing worn pads on a fresh rotor surface
Skipping the pad and rotor bedding process
Not cleaning or inspecting the hat, hardware, and mounting faces
Ignoring brake fluid condition during brake service
Ordering the wrong configuration for the vehicle or hat type

Taking care of these details helps the new rotor deliver the braking feel, wear life, and consistency it was designed to provide.

Recommended Companion Parts

Rotor service is also a good time to inspect or replace the brake pads, rotor hardware where applicable, and brake fluid. On performance applications, fresh pads and fluid often have as much impact on brake feel as the rotor itself.

Need help confirming fitment or choosing the right supporting parts?
Our team specializes in performance brake systems and can help you choose the right combination for your vehicle and how you use it.

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