DBA DBA4789 4000 Series HD Rear Disc Brake Rotor 330mm

The DBA DBA4789 is a 4000 Series HD rear disc brake rotor engineered by Disc Brakes Australia (DBA) for drivers who demand upgraded braking performance beyond standard OE levels. Featuring a smooth OE-style rotor finish, the 4000 Series HD is ideal for those who want the advanced internals of the DBA 4000 platform with a clean, factory-style appearance — making it popular for controlled race divisions and performance street use alike.

At the core of the DBA4789 is DBA's proprietary Kangaroo Paw ventilation system, which uses 144 diamond and teardrop-shaped internal pillars to deliver up to a 30% increase in surface area and up to 20% improvement in cooling efficiency compared to traditional straight vane designs. This advanced vane geometry accelerates airflow through the rotor, reducing heat buildup and extending brake pad and rotor life under demanding conditions.

Every DBA 4000 Series rotor is cast from high-carbon alloyed iron (XG-150 grade) and subjected to DBA's proprietary Thermal Stability Profiling (TSP) process — a controlled heat-cycling treatment that relieves internal manufacturing stresses, realigns the iron microstructure, and maximizes thermal stability. The result is a rotor that handles the heat and stress of intense, repeated braking with reduced risk of surface cracking or metal fatigue.

Key Features:

• Rotor diameter: 330mm — rear axle fitment
• Smooth OE-style finish (HD variant) — no suffix in part number
• 144-pillar Kangaroo Paw vane design for up to 20% better heat dissipation
• High-carbon alloyed iron (XG-150) construction for superior strength and durability
• Thermal Stability Profiling (TSP) for maximum rotor stability under extreme heat
• Heat-indicator paint markings change color at specific temperature thresholds for rotor fatigue monitoring
• Non-friction areas painted to resist rust and enhance appearance
• Direct OE replacement — single-piece construction for straightforward installation
• Sold individually; two required per vehicle (rear axle)

The DBA DBA4789 is a direct-fit, drop-in upgrade that delivers measurably better braking performance and longevity over standard OEM replacement rotors, without sacrificing street-friendly driveability.