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Hayes Dominion A4 Disc Brake - front - black / bronze

Hayes Dominion A4 Disc Brake - front - black / bronze

Dominion's master cylinder is factory tuned for the shortest dead stroke possible and a crisp bite point. The Dominion A4 caliper utilizes four pistons in the most structurally rigid design possible. It features a cold-forged caliper and KingPin structural pad retention bolt that increases stiffness.

With a motorsports-inspired Two-Stroke dual port bleed system, industry-leading DOT 5.1 fluid and Kevlar hose, the hydraulic system is engineered for ultimate performance across all temperatures and easy maintenance.

Dominion A4 features the proprietary QuickBite system for fast and consistent burnish, coupled with the D-Series rotor to manage the heat with less braking noise.

Highlights of the Hayes Dominion A4 Disc Brake

  • Four-Piston Technology
  • Low Input - High Fidelity (LoFi) - Low effort system with predictable, progressive ramp up and a crisp bite point.
  • Reduced Friction - A featherlight lever feel is acheived through a combination of an added glide ring on the piston and sealed ball bearings at the lever blade pivot
  • SRL - Our Stable Rate Link delivers a consistent lever ratio regardless of reach
  • Precise Engagement - Each Dominion is factory set to have the lowest dead stroke possible and a crisp bite point
  • Built to last - Metal pistons are used to ensure that no matter the terrain or temperature your brake will continue to perform as it did on the first ride
  • Adjustable Reach - Adjust your lever reach with ease while on the trail thanks to an intuive adjustment knob design
  • Modal Resonance Cancellation (MRC) - FEA-optimized modal shapes of D-Series rotors are intentionally designed to oppose those of Semi-Met T106 and Sintered T100 pads, canceling out noise and vibration.

Details of the Dominion A4 Brake

The new lever of the Dominion is robust and the lever width can be adjusted without tools. By means of a 2 mm grub screw the position of the brake caliper can be adjusted at the brake fitting. The bolting is done with SRAM's Matchmaker technology, but there is also an adapter for Shimano's I-Spec 2 mounting.

The result is the Dominion A4 disc brake, which is suitable for trail, enduro, downhill as well as E-MTB use.

Ball bearing brake lever with tool-free idle travel adjustment

The focus of the brake lever is to achieve the highest possible braking force with little finger force. This is to avoid wasting power unnecessarily during hard braking. In order to allow for a strong grip, the master cylinder is factory tuned for the lowest possible idle travel. The lever of the Dominion is robustly designed and allows a tool-free adjustment of the lever width.

The brake lever can be mounted on the left or right side

Completely newly developed 4-piston brake caliper

The brake caliper of the Dominion A4 is a completely new development and promises extreme braking power. There is an adjustment for the lever travel and the associated position of the master piston. The disc brake promises intuitive braking performance and features a defined increase in braking force when the pads hit, providing high predictability and control. The caliper uses four pistons, the arrangement of which is intended to provide the most durable structure possible. The caliper itself is made from cold-forged aluminium and, in conjunction with the KingPin split pin used to attach the brake pads, increases the rigidity of the entire system. Hayes is also particularly proud of the bleeding system: the 4-piston caliper is equipped with two bleed holes, which should ensure optimal bleeding. The position of the brake caliper is adjustable at the brake screw connection via 2 mm grub screw.


Scope of delivery:

  • hydraulic disc brake set, filled and bled consisting of brake lever, brake caliper and brake line (front 100cm / rear 180cm)
  • incl. 2 pairs of brake pads (sintered and semi-metallic)

Fact Sheet of Hayes Dominion A4 Disc Brake - front - black / bronze

Product Name: Hayes Dominion A4 Disc Brake - front - black / bronze
Manufacturer: Hayes
Item Code: HAY400649
activity: Cycling
usage bikesport: MTB
disc brake mount: Postmount
brake actuation: Hydraulic
brake lever version: Flat bar / Riser
brake lever style: 2-Finger
brake fluid: DOT 5.1
Disc brake - version: # Front Wheel, Set caliper & lever
Model year: 2022
Color: Black, Metallic
weight: 310g
manufacturer item code: 95-36115-K001
Manufacturer page: http://www.hayesdiscbrake.com/