The EBC GD1838 is a front rotor from the manufacturer's 3GD Series Sport line. It is a vented disc with both dimples and slots, precision-machined from premium castings. The manufacturer says the wide-aperture slots pull cooler air across the friction surface and expel dust, debris and pad gases, while the dimpling is meant to prevent stress cracking. For a 2.0T A4 used for spirited back-road runs or track days, that cooling and gas-venting design is the practical reason to upgrade from stock. The manufacturer also says the pattern helps pads wear flat and parallel for more consistent contact. Search terms: EBC GD1838 2.0T A4 front rotors, dimpled slotted 320mm Audi brake rotor, B8 A4 brake fade upgrade.
Listed for the 2012–2016 Audi A4 2.0 Turbo, these rotors are sold as a pair, measure 320 mm in diameter and 30 mm in thickness, and use five bolt holes. The manufacturer's fitting guidance calls for replacing rotors in pairs. Published year and trim coverage varies between sources, so confirm fitment for your specific vehicle with the manufacturer before ordering.
Per the manufacturer's fitting instructions, new pads should always be installed with new rotors, since worn pads on fresh discs can create hot spots. Hub condition is a common cause of runout, so clean the hub thoroughly, mount the rotor with washers under the lug nuts, and check axial runout with a dial indicator before final torque to Audi's specification. The manufacturer recommends 300 to 500 miles of gentle driving to bed in the pads and rotors. Brakes are safety-critical, so follow Audi's procedure closely.
The manufacturer states that new pads must always be fitted after installing new rotors, because using worn pads on new rotors may create hot spots that damage them.
The manufacturer advises always replacing rotors in pairs.
The manufacturer's fitting instructions call for 300 to 500 miles of cautious driving so the pads and rotors can bed in before normal braking.
The manufacturer's fitting instructions list a dial indicator, jack and stands, wheel chocks, the correct wheel socket, a torque wrench set to the vehicle manufacturer's wheel nut specification, and brake cleaner with a clean rag. Replacing the front rotors involves removing the caliper and wheel and checking the hub surface. Mount the new rotor with several wheel nuts snugged loosely, not one or two, to avoid skewing the disc. Then measure runout, and if it exceeds about 0.15–0.20 mm, the manufacturer says to remove the rotor, rotate it one bolt hole, and re-test. Poor hub condition is the main cause of runout problems, and an improperly prepared hub can void the rotor warranty.
