Hella 355118942 Vented Disc Brake Rotor 300mm 6x112

The Hella 355118942 is a vented, one-piece disc brake rotor built for daily driving and honest stopping power. It measures 300 millimeters across the outside diameter, runs 22 millimeters of nominal thickness, and stands 57.10 millimeters tall from the mounting face to the top of the hat. If your vehicle calls for a 300mm rotor on a 6 x 112 millimeter bolt pattern with a 67 millimeter center bore, this is the size you're looking at.

Vented is the key word here. The rotor is cast with internal cooling vanes between the two friction faces, so air pulls through the disc as the wheel spins. That airflow carries heat away from the pads and the rotor surface, which is exactly what you want on a heavier vehicle, in stop-and-go traffic, or on a long grade where the brakes stay busy. Solid rotors run hotter and fade sooner. A vented disc this size gives you more thermal headroom and a more consistent pedal feel when things heat up.

It's a one-piece design, meaning the hat and the friction ring are cast as a single piece of gray cast iron rather than bolted together. Fewer parts, nothing to work loose, and a straightforward install. Gray cast iron is the standard material for brake rotors because it sheds heat well and gives the pad a stable, predictable surface to bite into. Hella finishes the non-friction areas, the hat and the edges, with a zinc coating. That coating fights the surface rust that shows up fast on bare cast iron, especially around the wheel bolts and the center bore where you can see it through the wheel. The friction faces stay bare, the way they should, so the pads seat cleanly.

Fitment comes down to three numbers. The 6 x 112 millimeter bolt pattern has to match your hub. The 67 millimeter center bore has to slip over your hub register. And the 300 millimeter diameter with 22 millimeter thickness has to match the caliper and carrier your vehicle came with. Check those against your application before you order. This rotor is sold as a single, so for an even, balanced job you'll want two, one for each side of the axle. Brakes work in pairs, and mixing a fresh rotor with a worn one on the same axle pulls the car to one side under braking.

When you install it, this is a good time to fit fresh pads. A new rotor and old, glazed pads never seat well together, and you lose the benefit of the new disc. Clean the hub face so the rotor sits flat, torque the caliper bracket and wheel bolts to your vehicle's spec, and then bed the brakes in. Bedding means a series of moderate stops to transfer an even layer of pad material onto the rotor face. Skip that step and you invite uneven deposits, which is what most people feel as a shudder through the pedal later on.

Speaking of thickness, the 22 millimeter figure is the nominal, new dimension. Every rotor has a minimum thickness below which it should be replaced, and that discard figure is cast or stamped into the hat. As the pads wear the rotor down over the years, measure it with a micrometer and compare against that stamped number. Once it's at or near the limit, don't resurface it, replace it. A rotor that's too thin can't handle heat and is far more likely to warp.

Who's this for? Anyone doing a straightforward brake refresh on a vehicle that runs the 6 x 112 pattern and a 300mm vented disc. It's a sensible, correctly sized replacement rotor from a name that's been making braking hardware for a long time. Match the specs, buy a pair, fit good pads, bed them in, and you're back on the road with a firm pedal.