Hella 355122922 Vented Disc Brake Rotor 360mm 6x120

The Hella 355122922 is a vented, one-piece disc brake rotor cast from gray iron and finished with a zinc coating. It measures 360 millimeters across the outer edge, stands 62 millimeters tall overall, and runs 30 millimeters thick at the nominal friction face. If you're chasing down a worn or warped rotor and your vehicle uses the 6 x 120 millimeter bolt pattern with a 79 millimeter hub bore, this is the size you're looking at.

Let's talk about why the vented design matters. A vented rotor has two friction faces with cooling vanes cast between them. Air pulls through those vanes as the wheel turns, and that airflow carries heat away from the braking surface. Heat is the enemy of a brake system. When a rotor can't shed heat fast enough, the pads start to fade, the pedal goes soft, and stopping distances stretch out right when you need them not to. The 30 millimeter thickness here gives the rotor plenty of iron mass to soak up heat on a hard stop, and the vanes give it somewhere to dump that heat before the next one.

The one-piece construction keeps things simple and strong. The hat and the friction ring are cast as a single unit, so there's nothing to loosen or shift over time. Gray cast iron is the standard material for a reason. It handles repeated heat cycles well, it machines cleanly if you ever need to true it, and it delivers a consistent, predictable bite against the pad. The zinc coating is there to fight corrosion. Rotors that sit exposed to road salt and rain will surface-rust fast, and while the swept area cleans itself every time you brake, the hat, edges, and vanes stay protected. That keeps the rotor looking right behind an open wheel and stops rust from creeping into places the pads never touch.

Fitment is where you need to slow down and check. The 6 x 120 millimeter bolt pattern and 79 millimeter hub bore are common on a range of General Motors trucks and SUVs, but bolt pattern alone doesn't guarantee this is the correct rotor for your vehicle. Rotor diameter, thickness, and offset all have to match what the factory spec'd. Before you order, pull your current rotor's part number or measure the outside diameter and thickness, and confirm they line up with the 360 millimeter and 30 millimeter figures listed here. A rotor that's close but not exact will either not clear the caliper or won't seat flat against the hub, and neither one is safe.

This listing is for a single rotor. Brakes work as a matched set across an axle, so if one side is worn or warped, the other side is usually right behind it. We'd tell you to replace rotors in pairs, left and right on the same axle, so the braking force stays even from side to side. Fresh pads at the same time are cheap insurance too. New pads bed in cleanly against a fresh surface, and you avoid dragging old, glazed pad material across a brand-new rotor.

Installation is straightforward for anyone who's done a brake job before. You'll lift the vehicle, pull the wheel, unbolt the caliper and bracket, slide off the old rotor, and clean the hub face so the new rotor sits dead flat. Any rust or debris on that mating surface can cause runout, which shows up as a pulsing pedal. Wipe the zinc-coated swept faces with brake cleaner to remove any handling residue before you install the pads. Then bed the brakes in properly with a series of moderate stops so the pad material transfers evenly across the surface. Skip that step and you invite uneven deposits and vibration.

Who's this for? Anyone doing routine brake maintenance or a repair on a vehicle running the 6 x 120 pattern who wants a clean replacement rotor that matches factory dimensions. It's a service part, plain and simple. It does its job, resists corrosion, and gets you back on the road with a firm pedal. Just confirm the measurements against your vehicle first, buy two if you're doing a full axle, and bed them in right.