Brembo 09.C988.21 PRIME UV Coated Rear Disc Brake Rotor 2017-2024 Porsche Cayenne 330mm OE Replacement

The Brembo 09.C988.21 is a direct OE-replacement rear disc brake rotor engineered specifically for the 2019-2024 Porsche Cayenne (9YA) and 2020-2024 Porsche Cayenne Coupe (9YB) equipped with the 330mm standard rear brake package (PR codes 1KV or 1KR). Part of the Brembo PRIME product line, it is manufactured in Italy to factory-specification tolerances and carries ECE-R90 certification, the European safety standard that governs brake component performance. Brembo supplies brake systems directly to Porsche as an OEM partner, meaning this rotor is built to the same standards as the parts that left the Stuttgart factory. It ships with mounting hardware and is protected by a 24-month warranty from the date of delivery.

Brembo PRIME: OE Quality for Your Porsche Cayenne

The PRIME line is Brembo's OE-equivalent replacement tier, positioned for drivers who want factory-matched performance without compromise. Every rotor in this line is cast from high-carbon cast iron, the same material specification used in original Porsche production, which delivers superior fade resistance and quieter operation compared to standard gray-iron rotors. The internal vane design draws heat away from the friction faces through convection, maintaining consistent pedal feel during aggressive braking on canyon roads or track days.

The defining feature of the 09.C988.21 is its full UV-painted finish. Rather than the standard bare-metal or simple e-coat used by many aftermarket suppliers, Brembo applies an environmentally friendly water-based UV-cure paint across the entire rotor body, including the hat and vanes. This process delivers outstanding corrosion resistance from day one, eliminating the rapid surface rust that appears on uncoated rotors sitting on brake pad surfaces during the first week after installation. For a Cayenne owner who expects the engine bay and undercarriage to look as good as the interior.

Technical Specifications: What the Numbers Mean

The 09.C988.21 measures 330mm (12.99 in) in diameter with a nominal thickness of 26mm (1.02 in) and a minimum discard thickness of 24mm (0.945 in). The 2mm wear margin is a conservative factory figure that ensures predictable braking well before the rotor reaches its structural limit. The centering bore diameter of 98mm (3.86 in) mates directly to the Cayenne's rear hub with zero runout shimming required when installed correctly.

The rotor is plain-faced, with no cross-drilling or slotting. On a luxury SUV used primarily on public roads, a plain rotor offers longer pad life, consistent torque across the friction surface, and no risk of stress cracking that can develop around drilled holes under repeated thermal cycling. It is the configuration Porsche specifies from the factory for this brake package, and it replicates that specification exactly.

Fitment: 2017-2024 Porsche Cayenne and Cayenne Coupe (330mm Rear Brake Package)

The 09.C988.21 fits the rear axle of the Porsche Cayenne 9YA generation and the Cayenne Coupe 9YB generation with the 330mm standard rear brake package only. This brake package is identified by Porsche PR codes 1KV or 1KR. Vehicles equipped with the larger optional rear brake packages (PR codes 1KX, 1KS, 1KU, 2EN, or 2EI) require a different rotor: use Brembo 09.C987.21 for those applications. If you are uncertain which PR code your vehicle has, the build sticker in the driver door jamb or the factory window sticker (Monroney) will list the PR code. European-spec Cayenne production from 2017-2018 (pre-facelift 9YA) also fits.

This is a single-rotor listing. Order two to complete a full rear axle service.

Full Specifications

What's Included

• 1 x Brembo PRIME 09.C988.21 rear disc brake rotor (single)
• Fixing / mounting screws hardware pack

This is a single-rotor listing. For a complete rear axle brake service, add two units to your cart.

Complete Brembo PRIME Brake Rotor Set for the Porsche Cayenne 9YA / 9YB

Brembo offers the full front and rear rotor set for the 9YA/9YB Cayenne platform in the PRIME line. Note that front rotors are handed (left and right are separate parts), and the rear uses a different rotor for the larger optional brake package.

Warranty and Your Vehicle's Factory Coverage

The Brembo 09.C988.21 carries a 24-month warranty from the date of delivery, covering manufacturing defects in material and workmanship. This is a direct OE-replacement part meeting or exceeding the original Porsche specification, and ECE-R90 certified.

Installing this rotor will not void your Porsche factory warranty on unrelated components. Under the federal Magnuson-Moss Warranty Act, a manufacturer or dealer cannot void your vehicle's warranty simply because you installed an aftermarket or OE-equivalent replacement part. To void coverage on a specific component, they must demonstrate a causal link between the aftermarket part and the failure being claimed. A Brembo OE-specification rotor, which Brembo supplies to Porsche directly as a factory OEM supplier, presents no such risk for normal brake wear claims.

About Brembo

Brembo is the world's foremost manufacturer of high-performance braking systems and a direct OEM supplier to Porsche, Ferrari, Lamborghini, BMW, and virtually every other performance marque. Founded in Italy in 1961 and headquartered in Bergamo, Brembo supplies original brake systems to Porsche for the Cayenne, Panamera, and 911 product lines. This rotor is not a generic aftermarket supplier that approximates the factory specification; it is manufactured by the same company that produces Porsche's factory brakes, to the same material and dimensional tolerances. When you fit a Brembo PRIME rotor, you are fitting the supplier's own OE-equivalent part.

Installation Overview

The 09.C988.21 is a direct bolt-on replacement for the factory Cayenne rear rotor. No cutting, drilling, or welding is required. The included mounting hardware replaces the OEM retaining screws. A professional installation on a lift is recommended for Porsche service work, but the part itself requires no special tooling beyond standard brake service equipment.

• Position: rear axle only, both sides (order 2 for full axle service)
• Confirm PR code 1KV or 1KR before installation: see door jamb build sticker
• OEM cross-reference: Porsche part number 9Y0615601
• Minimum discard thickness: 24mm (0.945 in.): do not machine below this figure
• UV coating on hat and vane areas is cosmetic and non-structural; do not abrade the friction face before bedding
• Bed brakes per Brembo's recommended break-in procedure after installation
• Hardware (fixing screws) is included; no separate hardware kit required

Frequently Asked Questions

Is the 09.C988.21 the correct rear rotor for my 2021 Porsche Cayenne GTS?
Yes, if your 2021 Cayenne GTS is equipped with the standard 330mm rear brake package (PR code 1KV or 1KR), this rotor is the correct fitment. Check the PR code on your door jamb build sticker. If the code reads 1KX, 1KS, 1KU, 2EN, or 2EI, you need Brembo 09.C987.21 instead.

What is the difference between the 09.C988.21 and Brembo 09.C987.21 for the Cayenne?
Both rotors are 330mm in diameter and fit the Cayenne 9YA / 9YB rear axle, but they are not interchangeable. This rotor has a nominal thickness of 26mm and fits vehicles with PR code 1KV or 1KR. The 09.C987.21 is 28mm thick and fits the larger optional rear brake package (PR codes 1KX, 1KS, 1KU, 2EN, 2EI). Thickness is not interchangeable between these two packages, so confirm your PR code before ordering.

Does the 09.C988.21 fit the Cayenne Coupe?
Yes. The Cayenne Coupe (9YB generation, 2020 and later) shares the same rear brake architecture as the Cayenne 9YA. This rotor fits all Cayenne Coupe variants equipped with PR code 1KV or 1KR, including the Turbo GT Coupe (2022-2024).

Does the 09.C988.21 fit the Cayenne Turbo S E-Hybrid?
Yes. The Cayenne Turbo S E-Hybrid (4.0L V8 PHEV) fits this rotor from 2020 through 2024, provided the vehicle's rear brake package is the standard 330mm configuration with PR code 1KV or 1KR. High-output PHEV variants often come from the factory with uprated brakes, so verifying the PR code is especially important on this trim.

What is ECE-R90 certification and why does it matter for a Porsche rotor?
ECE-R90 is the United Nations Economic Commission for Europe Regulation 90, which sets mandatory performance standards for replacement brake discs sold in Europe. To earn ECE-R90 approval, a replacement rotor must pass friction performance, thermal stability, and dimensional accuracy tests against the OE benchmark. For a Porsche owner, ECE-R90 certification on this rotor is assurance that the rotor's stopping performance has been verified to match the Porsche factory specification, not just dimensional fit.

Will the 09.C988.21 void my Porsche warranty?
No. Under the federal Magnuson-Moss Warranty Act, an OEM-equivalent replacement part installed during routine maintenance cannot void your factory warranty unless the installer can demonstrate a direct causal link between that part and a specific failure. Brembo is Porsche's own OEM brake supplier, so this part presents zero elevated risk to any remaining factory coverage.

What is the minimum (discard) thickness for the 09.C988.21?
The minimum discard thickness is 24mm (0.945 in.). The rotor ships at a nominal 26mm. You have 2mm of wear margin before the rotor must be replaced. Machining the rotor is not recommended once it is at or below 24mm; replace it at that point.

Why does the 09.C988.21 have a UV-painted finish instead of bare metal?
Brembo applies a water-based UV-cure paint to the full rotor body (hat, vanes, and non-friction areas) to prevent surface corrosion during shipping, storage, and the initial period after installation. Bare or e-coated rotors develop orange surface rust on the hat and vanes within days in humid climates, which is primarily cosmetic but can create noise on initial application. The UV coating prevents this. The friction faces will burnish clear during the bedding process; the coating on the hat and other non-friction areas remains in place permanently and does not interfere with braking performance.

Does the 09.C988.21 fit European-spec Cayenne models from 2017-2018?
Yes. The 9YA generation Cayenne entered European production before the North American market launch. European-spec 2017 and 2018 Cayenne models in 3.0L V6, 2.9L V6 Twin-Turbo (S), and 4.0L V8 Turbo configurations with the standard 330mm rear brake package (PR code 1KV or 1KR) are covered by this rotor.

How many rotors come in a box? Do I need to order two?
This is a single-rotor listing. One box contains one rotor plus the included hardware. Brake rotors should always be replaced in axle pairs for balanced braking. To complete a full rear axle service, add two units to your cart.

Is this the same rotor Porsche uses from the factory?
Brembo is a direct OEM supplier to Porsche. The PRIME line uses the same high-carbon cast iron material, the same dimensional specifications, and the same manufacturing processes as Brembo's OEM production. The Porsche OEM cross-reference for this application is part number 9Y0615601. This part is Brembo's own aftermarket catalog number for the identical specification.

What brake pads are compatible with the 09.C988.21?
Any brake pad compound rated for the 330mm Porsche Cayenne rear application is compatible. Brembo offers its own PRIME and HP pad lines for this vehicle. OEM Porsche pads (Porsche part number cross-referencing the 9YA/9YB rear) will also seat correctly. Avoid mixing heavily worn pads against a new rotor; replace pads and rotors together for best initial bedding results.