HAYES DOMINION A4 Disc Brake Set Front/Rear Gray Hayes

Staff Shizuoka's Top Pick: Brake Set

Despite its powerful stopping force, the lever feel is incredibly light, making it easy to control and reducing arm fatigue.

Especially on downhill rides, you can concentrate on riding with confidence.

*Color is gray, sold as a pair (2 sets) for one bike. If you only need one set, please contact us.

The award-winning Dominion A4 is a 4-piston disc brake designed for ultimate stopping power and control. It incorporates motorsport-inspired technology to deliver peak performance across all temperatures.

Key Features & Technologies

• Low Input - High Fidelity (LoFi): Operates with light force, providing predictable and progressive braking power and a crisp bite point.
• Ultimate Caliper Rigidity: Features a cold-forged caliper with Ø17mm 4-pistons. The KingPin pad retention bolt further enhances rigidity.
• Minimal Dead Stroke: The master cylinder is factory-tuned to minimize the play between pulling the lever and brake engagement.
• Crosshair Caliper Alignment: Utilizes a screw mechanism for quick and precise micro-adjustment of caliper position, reducing setup stress.
• MRC (Modal Resonance Cancellation): When paired with D-series rotors, it suppresses resonance, canceling brake noise and vibration.
• SRL (Short Reach Lever): A short reach model is available for riders with smaller hands or those who prefer a closer lever position.

Technical Specifications

• Weight: 310g
• Hose Length: 180cm (Kevlar)
• Fluid: DOT 5.1
• Piston Diameter: 17mm
• Lever Adjustment: Tool-free reach adjustment
• Lever Pivot: Sealed cartridge bearing
Flip-flop Design: The lever can be used on either the left or right side.

Package Contents

• Dominion A4 brake unit
• Includes 2 types of brake pads:
  • Semi-Met T106 (installed in caliper)
  • Sintered T100 (included as spare)

*Rotors and mounting brackets are sold separately.

Notes on Purchase

• The hose diameter of this product is 5.5mm. Some frames (e.g., Specialized Turbo Levo, Stumpjumper, etc.) may require modification or ingenuity to pass through their internal routing guides.
• When tightening the master cylinder's bleed screw, please avoid excessive torque (specified at 1.5nm).