Hella 355122952 Vented Disc Brake Rotor, 322mm 6x112

The Hella 355122952 is a direct-replacement disc brake rotor built to bring a worn braking system back to full strength. It's a vented, one-piece casting in gray iron, measuring 322 mm in outside diameter with a 32 mm nominal thickness and an overall height of 64.30 mm. The center hub bore is 67 mm and the wheel bolt pattern is 6 x 112 mm. When those numbers line up with what's already on the vehicle, this rotor bolts on with no modification.

The vented design is the part that matters most under hard use. Two friction faces separated by internal cooling vanes let air pull heat out of the rotor as the wheel spins. That keeps temperatures down during repeated stops, and cooler rotors mean more consistent pedal feel and less brake fade on a long downhill grade or in stop-and-go traffic. A one-piece casting keeps the whole disc rigid, so you get even pad contact and less chance of the vibration that shows up when a rotor warps.

Hella finishes this one with a zinc coating over the gray iron. That's a real advantage if you park outside or drive where the roads get salted in winter. Bare cast iron starts surface-rusting almost immediately, and while the friction faces wear clean every time you brake, the hat and the edges don't. The zinc coating keeps those non-wearing areas clean and stops the flaky orange rust that makes an older wheel look neglected. It also makes the next brake job easier, because the rotor won't have seized itself to the hub.

Fitment comes down to the numbers, so measure before you order. Check the bolt pattern (6 x 112 mm), the outside diameter (322 mm), the nominal thickness (32 mm), and the center bore (67 mm) against the rotor you're pulling off. Vented front rotors in this size range are common across a lot of platforms, but the only thing that guarantees a fit is matching the dimensions and the bolt pattern exactly. If any one of those is off, it's the wrong disc for your hub.

How do you know it's time? Rotors wear down every time the pads squeeze them, and eventually they drop below the minimum thickness stamped on the disc. Signs you're due include a pulsing or shuddering pedal under braking, a scoring groove you can feel with a fingernail, a lip built up around the outer edge, or visible cracks and deep rust pitting on the friction face. Once a rotor is at or below minimum thickness it can't be resurfaced safely, and it's time for a replacement like this one.

A few notes from doing this work. Replace rotors in axle pairs, never just one side. Braking has to be balanced left to right, and a fresh disc against a worn one on the other wheel will pull. Fit new pads at the same time, since old pads carry a wear pattern and a transfer layer that won't match a new surface. And bed the brakes in properly after the install, a series of firm slowdowns from moderate speed to seat the pads and lay down an even transfer layer. Skip that step and you invite uneven deposits and a pulsing pedal down the road.

Gray cast iron is still the material of choice for a reason. It handles heat well, damps vibration and noise, and wears in a predictable, pad-friendly way. This casting pairs that proven material with the vented, one-piece format that most modern disc setups are designed around, so you get replacement performance that matches what left the factory rather than a compromise. It's sold as a single rotor, so order the quantity your axle needs, torque the wheel and caliper hardware to the vehicle's spec, and you're back to a firm, quiet pedal.