Hella 355112122 310mm Vented Disc Brake Rotor
Hella 355112122 310mm Vented Disc Brake Rotor — Product description
The Hella 355112122 is a vented, one-piece disc brake rotor cast from zinc-coated gray iron. It runs 310 millimeters across, 22 millimeters thick, with a 65 millimeter hub bore and a 112 millimeter bolt circle. The vented core sheds heat under load, and the zinc coating keeps surface rust off the hat and vanes. Match the specs to your vehicle before ordering.
This is the Hella 355112122 disc brake rotor, a vented, one-piece casting that brings a worn brake corner back to spec. It measures 310 millimeters across the outside, runs 22 millimeters at nominal thickness, and stands 48.5 millimeters tall from the hub face to the friction ring. The center bore is 65 millimeters and the mounting face carries a 112 millimeter bolt circle. If those four numbers match what's on your vehicle right now, this rotor drops in.
Let's talk about why it's vented. A vented rotor is really two friction faces with cooling vanes cast between them. Those vanes pull air through the middle of the disc as the wheel turns, and that airflow is what keeps the surface temperature down when you're hauling a load or riding the brakes down a long grade. Solid rotors are fine on light-duty rear corners, but anywhere the brakes work hard, vented is what you want. Heat is the enemy of braking. It's what fades your pedal and warps a disc, and this casting is designed to shed it.
The one-piece design matters too. The friction ring and the hat are cast as a single unit of gray cast iron, so there's nothing to loosen, shift, or corrode between two mating parts over time. Gray cast iron is the workhorse material for brake rotors because it handles repeated heat cycles without cracking and it machines cleanly if a shop ever needs to true it. Hella finishes this one with a zinc coating, which is the part you'll appreciate a few months down the road. Bare cast iron surface-rusts almost immediately once it's exposed to road spray and humidity. The zinc keeps the hat, the vanes, and the edges looking clean and slows the corrosion that otherwise eats at the non-friction surfaces.
This is sold as a single rotor. One important habit: replace rotors in pairs across an axle. Even if only one side is scored or below minimum thickness, a fresh rotor on one corner and a tired one on the other gives you uneven braking, and you'll feel it as a pull under hard stops. Buy two if you're doing the axle, and put fresh pads on at the same time. New pads bedded against an old glazed rotor never seat right.
Installation is straightforward for anyone who's turned a wrench on a brake job. Pull the caliper and bracket, slide the old rotor off, and clean the hub face down to bare metal so the new rotor seats flat. Any rust or crud trapped between the hub and the rotor hat will translate into runout, and runout is what gives you that pulsing pedal. Wipe the protective film off the new rotor's friction surfaces with brake cleaner before you install. Then torque the wheel in a star pattern to your vehicle's spec, never straight around, or you can distort the disc and chew your pads.
Bed the brakes in before you rely on them. A series of moderate stops from moderate speed, without coming to a complete halt, lays an even transfer layer of pad material onto the fresh surface. Skip that step and you invite uneven deposits, which show up later as a vibration you'll swear is a warped rotor.
A couple of honest notes. This is a specific casting with a specific bolt pattern, hub bore, diameter, and thickness. It's not a universal part. Measure your current rotor or check the 355112122 part number against your application before you order, because a rotor that's close but not exact simply won't bolt up. And if you're chasing a pedal pulsation, replace the pads and clean the hub at the same time. A new rotor alone rarely fixes a problem that started with contaminated pads or a dirty hub face.
Key Features
- Vented rotor design pulls cooling air through internal vanes to shed heat and resist brake fade under load
- One-piece gray cast iron casting handles repeated heat cycles without the loosening or corrosion of a two-piece hat
- Zinc coating protects the hat, vanes, and edges from the surface rust that road spray and humidity cause on bare cast iron
- 310 millimeter outside diameter for a larger, higher-capacity brake system
- 22 millimeter nominal thickness with a vented core
- 65 millimeter center bore and 112 millimeter bolt circle, match to your vehicle before ordering
- 48.5 millimeter overall height from the hub face to the friction ring
- Sold individually, replace in pairs across the axle for even, straight-tracking braking
- Gray cast iron machines cleanly if a shop needs to true it during a future service
Why Buy from NVN Marine
- Authorized Hella Marine reseller, full manufacturer warranty
- NMEA member and ABYC certified, advice from real boat techs
- Same-day shipping before 3 PM ET on in-stock items
- NY headquarters and Fort Lauderdale flagship retail store
Technical specifications
| Title | Hella 355112122 Vented Disc Brake Rotor |
|---|---|
| Brand | Hella |
| Manufacturer Part Number | 355112122 |
| UPC | 4082300573794 |
| Rotor Type | Vented |
| Design | One Piece |
| Wheel Bolt Pattern | 10 x 112 Millimeter |
| Outside Diameter | 310 Millimeter |
| Nominal Thickness | 22 Millimeter |
| Height | 48-1/2 Millimeter |
| Hub Size | 65 Millimeter |
| Material | Zinc Coated Gray Cast Iron |
| Quantity | Single |
Frequently asked questions
What are the dimensions of the Hella 355112122 rotor?
It's 310 millimeters in outside diameter, 22 millimeters at nominal thickness, and 48.5 millimeters in overall height. The center bore is 65 millimeters and the bolt circle is 112 millimeters. It's a vented, one-piece gray cast iron casting.
Is this a vented or a solid rotor?
Vented. There are cooling vanes cast between the two friction faces, and they pull air through the disc as the wheel turns. That airflow keeps surface temperature down under heavy braking, which is what resists fade and warping.
Does it come as a pair or a single rotor?
This part number is a single rotor. We always recommend replacing rotors in pairs across an axle so both corners brake evenly. If you're servicing one side, order two.
What does the zinc coating do?
It slows corrosion on the non-friction surfaces, the hat, the vanes, and the edges. Bare cast iron surface-rusts almost immediately once it sees road spray and humidity. The zinc keeps those areas clean and the rotor looking right months down the road.
Will this fit my vehicle?
Match the four numbers that matter: 310 millimeter diameter, 22 millimeter thickness, 65 millimeter hub bore, and 112 millimeter bolt circle. The safest check is to run part number 355112122 against your application. We can't confirm fitment from the listing alone, so verify before ordering.
Do I need new brake pads too?
We recommend it. New pads bedded against an old, glazed rotor never seat correctly, and a fresh rotor running against worn pads wears unevenly. Doing pads and rotor together on a corner gives you the best, quietest result.
How do I install it without creating a pedal pulsation?
Clean the hub face down to bare metal so the rotor seats flat, wipe the protective film off the friction surfaces with brake cleaner, and torque the wheel in a star pattern to your vehicle's spec. Trapped rust or crud between the hub and the rotor hat causes runout, which is what you feel as a pulsing pedal.
Can this rotor be resurfaced later?
Gray cast iron machines cleanly, so a shop can true it if it's within limits. Before turning it, measure the thickness against the minimum stamped for the application. Once a rotor is below minimum thickness it should be replaced, not machined.
