Hella 355114002 Vented Disc Brake Rotor 320mm 6x120

The Hella 355114002 is a vented, one-piece disc brake rotor built from zinc-coated gray cast iron. It measures 320 millimeters across the outside diameter with a 20 millimeter nominal thickness, so it's a full-size rotor meant for a vehicle with real stopping demands, not a compact economy setup. If you're replacing worn or warped rotors and you want a straight-up cast iron replacement that bolts on and gets you back on the road, this is that part.

Vented is the key word here. The rotor has internal cooling vanes cast between two friction faces, and those vanes pull air through the disc as the wheel turns. That airflow sheds heat, and heat is what kills brakes. On repeated hard stops, towing, or long downhill grades, a vented rotor stays cooler than a solid one, which means less fade and less chance of warping. One-piece means the hat and the friction ring are cast as a single unit, so there's nothing to come loose and nothing extra to torque.

The zinc coating is there to fight corrosion. Bare cast iron surface-rusts almost immediately once it's exposed to moisture and road salt, and while the friction faces wipe clean every time you touch the brakes, the hat, the edges, and the vanes don't. The zinc keeps those non-wear surfaces from turning into a rust bloom. It's a longevity win, especially if the vehicle sits outside or sees winter roads.

Fitment comes down to three numbers, and all three have to match your vehicle. The wheel bolt pattern is 6 x 120 millimeter, so six studs on a 120 millimeter circle. The center bore, or hub size, is 75.1 millimeters, which is the hole in the middle that centers the rotor on the hub. And the outside diameter is 320 millimeters, which has to clear your caliper and your wheel. Overall height on the hat is 78 millimeters. Before you order, pull your old rotor or check your OE spec and confirm those numbers line up. A rotor that's a hair off on bore or diameter won't sit right.

A couple of install notes from experience. Replace rotors as a set on the same axle whenever you can. Mixing a fresh rotor with a worn one on the other side gives you uneven braking, and that's a pull you'll feel in the wheel. Fresh rotors also like fresh pads, so if the old pads are glazed or low, swap them at the same time and bed everything in properly. And torque your wheel studs in a star pattern to spec. Cranking them down unevenly is the fastest way to introduce runout and end up chasing a pulsing pedal you didn't have before.

Who's this for? Anyone doing a straightforward brake refresh who wants a solid cast iron replacement rotor at a fair price. It's a gray cast iron casting, the same material the vast majority of factory rotors are made from, so you're getting proven, predictable braking behavior. It's not a drilled or slotted performance disc, and it's not trying to be. If your driving is normal street use, daily commuting, hauling, and the occasional spirited stop, a quality vented cast iron rotor like this is exactly what you want. Slots and cross-drilling look great but they mostly matter on the track, and they can actually shorten pad and rotor life on the street.

This one ships as a single rotor. Order two if you're doing both sides of an axle, which is what we'd recommend. The nominal thickness is 20 millimeters new, so make a note of your vehicle's minimum thickness spec and check it down the road. Cast iron wears, and once you're at the discard limit it's time for another set.

One last thing on bedding in. When everything's installed, find a safe stretch of road and do a series of moderate stops from around 35 to 5 miles per hour, then a few harder ones, letting the brakes cool between. That transfers an even layer of pad material onto the fresh rotor face and sets you up for quiet, consistent braking. Skip it and you're more likely to get squeal or an early pulse. Five minutes now saves you a headache later.