GiroDisc A2-155 380 mm 2-Piece Rear Rotors for 2005-2025 Porsche 981/718/991

Vehicle Fitment

• Porsche 981 Cayman GT4 (2015-2016) - rear axle (non-PCCB)
• Porsche 718 Cayman/Boxster GT4 or Spyder (982, 2016-2025) - rear axle (non-PCCB)
• Porsche 911 Turbo / Turbo S (991, 2011-2019) - rear axle (non-PCCB)
• Porsche 911 Carrera GTS / 911 Turbo / 911 Turbo S (992, 2019-2025) - rear axle (non-PCCB)

Features

• 2-piece floating rotor design - billet aluminum hat + high-carbon cast-iron rotor ring to reduce unsprung and rotational mass
• 380 mm slotted & vented disc - larger braking surface enhances heat dissipation and braking power
• Curved-vane internal ventilation - draws cooling air through the rotor under heavy braking or track use to maintain temperature
• Floating-mount hardware using high-strength alloy steel drive-pins, spring washers, and hardened cap screws - allows thermal expansion while preventing cold-start rattles
• Direct-bolt replacement - mounts directly to factory rear hubs and works with OEM rear calipers (no modifications required)
• Reusable hat design - when rotor rings wear or warp, you can replace only the cast-iron rings instead of entire rotor assembly
• Improved suspension response and braking modulation due to reduced rotating and unsprung mass - beneficial for street, spirited driving or track use
• Maintains factory brake bias, ABS function, and pad compatibility when proper pads are used

Specifications

• Part Number: A2-155
• Rotor Diameter: 380 mm
• Construction: 2-piece floating (6061-T6 aluminum hat + cast-iron ring)
• Disc Surface: Slotted & vented, with curved internal vanes for airflow
• Mounting: Floating mount via alloy steel drive-pins, washers, cap screws
• Sold As: Pair - left and right rear rotors including mounting hardware
• Fitment Note: For models without factory carbon-ceramic brakes (PCCB equivalent); verify caliper/pad setup before install

Included Components

• 2x Rear brake rotors (left + right), 380 mm 2-piece floating design
• Floating-mount hardware: drive-pins, spring washers, cap screws/bolts as needed

Product Description

The GiroDisc A2-155 rear rotor set is an engineered performance upgrade tailored for a wide array of Porsche models - including 981-series Cayman GT4, 718 Cayman/Boxster GT4-Spyder, and 911 (991/992) Turbo or GTS models (as long as they're equipped with standard iron rear brakes, not ceramic). The 380 mm slotted and vented disc increases braking surface and heat capacity, which improves braking performance and fade resistance during spirited driving or track use. The two-piece floating design - combining a lightweight aluminum hat and cast-iron ring - reduces unsprung and rotational weight, giving sharper suspension behavior, better braking modulation, and more responsive handling.

Because A2-155 bolts directly to the OEM rear hubs and works with stock calipers, installation is straightforward and retains factory brake balance and ABS functionality. The floating-mount hardware provides thermal expansion tolerance and self-centering, while anti-noise washers prevent cold-start rattle often associated with two-piece rotors. Additionally, the rotor rings are replaceable - when they reach service limit, only the rings need replacing, which reduces long-term maintenance cost. For Porsche owners seeking a direct-fit, durable, and performance-ready rear brake upgrade across multiple model generations - A2-155 delivers strong braking performance, improved handling feel, and long-term serviceability.