DBA DBA42551 4000 Series HD Rear Disc Brake Rotor

The DBA DBA42551 is a 4000 Series HD single-piece performance disc brake rotor engineered as a direct OE replacement for the rear axle. Designed for drivers who demand braking performance above and beyond stock levels while retaining a clean, smooth OE-style finish, the 4000 Series HD is a popular choice for controlled race divisions and performance street use alike.

Cast from XG-150 high carbon alloyed iron, this rotor is paired with DBA's proprietary Thermal Stability Profiling (TSP) process — a series of controlled heat cycles that relieve internal casting stresses, realign the iron's microstructure, and maximize thermal stability and fatigue resistance under repeated heavy braking demands.

At the heart of the rotor's ventilation system is DBA's patented Kangaroo Paw vane design — a precise arrangement of 144 diamond and teardrop-shaped pillars that delivers up to a 30% increase in surface area and up to 20% improvement in cooling efficiency compared to conventional straight vane designs. The result is significantly reduced brake fade and extended service life for both pads and rotors.

Key Features:

• 4000 Series HD variant — smooth OE-style rotor finish, suitable for controlled race divisions and performance street use
• Kangaroo Paw ventilation — 144 diamond and teardrop pillars for up to 30% more surface area and 20% better heat dissipation
• XG-150 high carbon alloyed iron construction — handles increased stress and heat from intense braking applications
• Thermal Stability Profiling (TSP) — proprietary heat treatment process for maximum rotor stability and reduced metal fatigue
• Thermo-Graphic Heat Paint (TGHP) — color-change paint markings indicate peak braking temperatures for informed pad compound selection
• Painted non-friction areas — corrosion protection for enhanced appearance and longevity
• Sold individually — single rotor

The DBA 4000 Series HD is engineered for enthusiasts who want the proven thermal and structural benefits of the 4000 Series platform in a smooth, understated finish. Pair with compatible DBA performance brake pads for optimal interaction with the TSP-treated friction surface.