Hella Pagid 355123112 Front Disc Brake Rotor, 345mm Vented

The Hella Pagid 355123112 is a front disc brake rotor built to the same standards as the part that came off your car at the factory. It's a one-piece, internally vented casting that measures 345 millimeters across the outside diameter with a 30 millimeter nominal thickness, sized for the front axle of the larger European sedans and SUVs that run a 345mm front brake. If your vehicle left the line with this rotor size, this is a straight replacement that goes on with your existing calipers, pads, and hardware.

Braking turns motion into heat, and a lot of it. The vented design puts a ring of internal vanes between the two friction faces, and those vanes pull cooling air through the rotor as the wheel spins. That airflow carries heat away from the pad contact surface, which is what keeps the brakes feeling firm on a long mountain descent or after a few hard stops in traffic. Cooler rotors resist the fade and the pedal softness that show up when a cheaper casting can't shed heat fast enough.

The casting is gray cast iron, the material brake rotors have used for decades because it grips consistently, runs quiet, and wears in a predictable, even pattern with the pad. Hella Pagid machines the friction faces to tight tolerances so the rotor runs true, which is what stops the steering-wheel shimmy and brake-pedal pulsation you feel when a rotor has too much thickness variation or runout. You get smooth, linear stopping feel instead of grabbiness.

The rotor carries a zinc coating across the hat, the vanes, and the outer edges, all the areas the brake pad never sweeps clean. Those are exactly the spots that turn orange with surface rust within a week on a bare rotor, and on a car with open-spoke wheels that rust is the first thing anyone sees. The coating keeps those surfaces looking finished and slows the corrosion that can otherwise creep under the pad track over a wet winter. The pad wipes the friction band clean every time you brake, so that part stays bright on its own.

Dimensionally, this is a 345 millimeter rotor with a 30 millimeter friction band, an overall height of 51.90 millimeters, and a 68 millimeter center hub bore, with a 6 by 112 millimeter mounting pattern. Those numbers matter, because a front rotor has to match your caliper and carrier exactly. The 345mm front size lands this rotor on the Audi A6, A7, and Q5 family among other European applications, but brake specs change across model years and engine options, so confirm the fitment against part number 355123112 and your VIN before you order.

This one's sold individually, which is the honest way to buy a rotor. Brakes work as an axle pair, so you'll want two of these for the front, and you should always replace both sides at the same time so the left and right brakes bite evenly. It's also smart to fit fresh pads whenever you put on new rotors, and to bed the new pads and rotors in with a series of moderate stops so the pad material transfers evenly onto the fresh surface. Skip the bedding step and you can end up with the very pulsation the true-running rotor was built to avoid.

A quick note on what this rotor isn't. It's not a cross-drilled or slotted performance upgrade, and it doesn't need to be. For a street car it's the smart choice, a smooth-faced OE-style rotor that runs cooler, quieter, and longer than a drilled disc that can crack around the holes under hard use. And it's specific to the 345mm front brake, so if your vehicle uses a different diameter or a rear rotor, this isn't the one. Match the size and the part number, and you're set.

Whether you're a shop knocking out a brake job or a driveway mechanic doing your own, the 355123112 is the kind of part Hella Pagid is known for. Fit it, torque it to spec, bed it in, and it'll give you quiet, confident stops for the long haul.