Brembo 09.N285.21 UV Coated Front Rotor for 2013-2018 Cadillac ATS J55 321mm

Vehicle Fitment

• 2013-2018 Cadillac ATS Sedan (Luxury, Performance, Premium Luxury, Premium Performance; 2.5L I4, 2.0T Turbo I4, 3.6L V6; RWD & AWD) - with Brake Code J55 (4-piston Brembo front calipers)
• 2013-2018 Cadillac ATS Coupe (Luxury, Performance, Premium Luxury, Premium Performance; 2.0T Turbo I4, 3.6L V6; RWD & AWD) - with Brake Code J55 (4-piston Brembo front calipers)

Fitment Notes

• BRAKE CODE SPECIFIC: This rotor fits ONLY Cadillac ATS models equipped with GM Brake Code J55 - the factory 4-piston Brembo front caliper package with 321mm rotors. Verify your vehicle's RPO/brake code before ordering. The code sticker is located under the trunk floor mat.
• Does NOT fit ATS models with the base single-piston front calipers and 300mm rotors (non-J55 brake package) - typically the Standard/base trim sedan with the 2.5L I4 engine without the Brembo option.
• Does NOT fit the Cadillac ATS-V (2016-2019) - the ATS-V uses a significantly larger 6-piston Brembo front caliper with a 370mm rotor, which is an entirely different part specification.
• The 4-piston Brembo J55 front brake package was standard on all ATS Coupe models and on ATS sedan trims Luxury and above. It was an available option on the base ATS sedan with the 2.5L engine.
• This rotor is NOT sided - a single part number fits both the left (driver) and right (passenger) front positions.
• Sold individually - two rotors are required for a complete front axle replacement.
• Replaces Cadillac OE part number 23118091.

Features

• Brembo Prime Line OE-equivalent design - engineered as a direct replacement for the factory 321mm front rotor paired with the ATS's 4-piston Brembo J55 caliper package, requiring no modifications or caliper bracket changes for installation.
• UV coating applied to the full rotor surface - including the braking plates, outer diameter, and hub - using a solvent-free, water-based process that provides superior corrosion resistance beyond the OE standard, ready to install right out of the box.
• Pillar Vented Technology (PVT) - Brembo's patented internal pillar venting maximizes airflow through the rotor, delivering up to 40% greater resistance to thermal cracking compared to conventional vane-vented designs.
• High-carbon cast iron construction minimizes brake noise and vibration while enhancing thermal stability and heat dissipation - especially important given the ATS's track-capable character and its factory-spec Brembo 4-piston front brake setup.
• Precision electronic balancing during production minimizes lateral runout, eliminating brake pedal pulsation and vibration for the sharp, responsive brake feel the ATS platform is known for.
• ECE R-90 certified - independently validated to meet European automotive safety and performance standards, confirming OE-equivalent stopping power.
• Non-sided design - a single part fits both driver and passenger front positions, simplifying ordering.
• Intelligent part marking - part number and minimum discard thickness stamped directly on the rotor for easy service interval identification.
• Includes fixing screw hardware kit - all required installation fasteners are in the box.

Specifications

• Position: Front (Left or Right - not sided)
• Rotor Type: Vented (Internally Ventilated)
• Outside Diameter: 321mm (12.64")
• Nominal Thickness: 30mm (1.18")
• Minimum Discard Thickness: 27mm (1.06")
• Hat Height: 61mm (2.40")
• Hat Inside Diameter: 160mm
• Centering Bore Diameter: 71mm (2.80")
• Number of Bolt Holes: 5
• Venting: Pillar Vented Technology (PVT)
• Coating: UV Coated (full rotor surface)
• Material: High-Carbon Cast Iron
• Applicable GM Brake Code: J55 (4-piston Brembo front calipers)
• Cadillac OE Cross-Reference: 23118091
• Units Per Box: 1

Included Components

• 1x Brembo 09.N285.21 UV Coated Front Disc Brake Rotor
• 1x Fixing screw/hardware kit for installation

Product Description

The Brembo 09.N285.21 is a Prime Line UV Coated vented front disc brake rotor engineered as the direct OE-equivalent replacement for the Cadillac ATS's factory 4-piston Brembo front brake package (GM Brake Code J55). Replacing Cadillac OE part number 23118091, this 321mm rotor was developed specifically for the ATS's track-tuned chassis - a platform notable for offering factory Brembo performance front brakes across virtually all trim levels, from the Luxury sedan through the Premium Performance coupe, on both 2.0T turbocharged and 3.6L V6 variants, in both rear-wheel-drive and AWD configurations. As the original supplier of the ATS's front brake system, Brembo's replacement rotor delivers the same dimensional accuracy, metallurgical quality, and braking feel as the factory unit.

Built from high-carbon cast iron and featuring Brembo's Pillar Vented Technology (PVT), the 09.N285.21 provides up to 40% greater thermal crack resistance than conventional vane-vented designs - a meaningful advantage on a compact performance sedan known for enthusiast driving and occasional track use. The UV coating shields the entire rotor surface, including the braking plates, using a solvent-free process that outperforms OE corrosion protection and allows installation directly from the box without brake cleaner prep. Precision electronic balancing minimizes lateral runout, preserving the crisp, linear brake pedal feel the ATS platform delivers with its fixed-caliper Brembo setup.

Before ordering, confirm your ATS is equipped with Brake Code J55 by checking the RPO sticker under the trunk floor mat. ATS models without J55 use a single-piston front caliper with a smaller 300mm rotor, and the ATS-V uses a 6-piston Brembo unit with a 370mm rotor - neither is compatible with this part. This rotor is not sided and fits both front positions. Two are required for a complete front axle service. For optimal braking performance, Brembo recommends replacing rotors and pads together and pairing with Brembo NAO Ceramic or Low-Met brake pad formulations.