Rick's Free Auto Repair Advice

Best brake rotors — an in depth explanation

Best brake rotors — what to look for

There are lots of offshore brake rotors on the market today and a high percentage are just plain garbage. They’re made with lower-grade metal, they don’t use the same cooling vane design, and the friction rings are thinner. So they don’t last as long or brake as well as premium quality rotors.

Here’s how to tell the difference between an economy brake rotor and the best brake rotors

Economy brake rotors are made with less metal

The two rotors shown below are for the same vehicle. The top image shows the weight of a premium brake rotor, while the bottom photo shows the weight of an economy brake rotor. The economy rotor is 2.6-lbs lighter, or 15% less metal. When it comes to heat dissipation, mass is everything. So the economy rotor can’t dissipate heat as well as the premium rotor, which means you’ll get more brake pad wear and more brake pad fade.

premium brake rotor

Premium quality brake rotor

economy brake rotor

Economy Rotor on scale

Economy brake rotors have thinner friction rings

If you look the thickness of the friction rings, you’ll see where the economy rotor manufacturer cut corners. The economy rotor has thinner friction rings.

The thinner friction ring can’t dissipate heat as well as the thicker friction ring. So it will degrade brake pad performance and wear out faster.

The thinner friction ring also means it can’t be resurfaced.

Image showing thicker friction ring on premium brake rotor

OEM brake rotor. Notice plate thickness

image showing the thinner friction ring on an economy brake rotor

Economy brake rotor. Notice the thinner plates?

Economy brake rotors have straight cooling vanes that don’t cool as well as the factory cooling vanes

It costs more to duplicate the carmakers’ cooling vane design than it does to make straight cooling vanes.

But the carmakers design these unique vane patterns for a reason; they cool better and provide better heat dissipation and better braking.

difference between brake rotors

Different brake rotor cooling vane designs

Economy brake rotors use lower quality gray iron

Most brake rotors are made from either medium carbon (G30) or high carbon (G20) gray iron. Medium G30 is used mostly for standard passenger vehicles, while G20 is often used for light trucks and SUVs.

However, according to a recent SAE study, “Rotor gray iron material varies considerably from one supplier to another even with the same grade of rotor iron specified.” — Fine-Tuning of Rotor Gray Iron Material for Optimal Brake Performance, SAE 2016-01-1942.

That’s why it’s important to purchase brake rotors from a reputable brake parts manufacturer.

Here’s a list of the MAJOR players in the brake parts business

ACDelco — owned by General Motors and a Tier 1 supplier to GM
Advics —
Beck Arnley — see Dr1V division of Tenneco Automotive below
Bendix See — see MAT Holdings and TMD Friction
Brembo — A Tier 1 supplier of brake calipers for Porsche, Mercedes, Lancia, BMW, Nissan and Chrysler.
Bosch — No longer owned by Robert Bosch. It is now owned by Chassis Brakes International
Centric — see First Brands Group
Monroe — see Dr1V division of Tenneco Automotive
Pagid — See TMD Friction
Raybestos — see First Brands Group
Wagner — see Dr1V division of Tenneco Automotive

There’s there’s the brake rotor coating issue

All brake rotors rust. That’s not a big issue for the friction ring (aka swept area) because the brake pads will wipe off the rust. But rust can also accumulate on the hat and mounting areas. Brake parts manufacturers have responded by offering electro-plated brake rotors.

You should buy premium brake rotors with electro-plating even if you don’t live in cold climates where road salt is used. Why? Because the electro-plating protects the cooling vanes from corroding, and proper cooling vane operation is critical to long rotor and pad life.

AC Delco Premium Brake Rotors

Made with Ferritic Nitro-Carburizing technology are hardened and strengthened during an extended manufacturing process. The cast iron rotor surface is bonded with nitrogen atoms under the intense heat of a giant, 1,040-degree oven. The additional atom layer provides an extra defensive barrier against the corrosive threat of water, salt, and even acid rain.

Advics Ultra-Premium Disc Brake Rotors

Emulter 3000 paint process, anti-rust wash, C40 and E-Coating protects against corrosion and ensures rotors are ready to install right out of the box

Produces optimal carbon content levels for improved fade resistance leading to increased durability and
longer rotor life

Bendix Premium Brake Rotors

OEM Driven Machining Specifications Ensure Smooth Pad-to-Rotor Contact and Trouble-Free Operation

OEM Style Vane Configuration

Premium Corrosion Protection Coating Provides a Clean Look and Extends Life with obstruction-free Airflow Venting

Bosch QuietCast Premium Brake Rotors

Premium-coated rotors are designed to prolong corrosion and maintain higher thermal stability, allowing for extended brake system longevity.

Centric Brake Rotors

Centric premium rotors utilize an electrocoating finish that provides long-lasting corrosion protection. E-coating is a superior, electro-statically applied finish designed to withstand 400 hours of saltwater exposure without rusting. Phosphate finishes utilized by other manufacturers provide only minimal protection from the elements; these finishes are generally only effective for the shipping and storage portion of a rotor’s life. The addition of heat and moisture eliminates the effectiveness of phosphate finishes, resulting in immediate corrosion once installed in the vehicle.

Raybestos Element 3 Brake Rotors

Our Element 3 coated rotors are coated on their entire surface with a proprietary full Grey Fusion 4.0 coating. The rotors are put through 300 plus hours of salt spray testing, which exceeds the OE requirement for car and truck rotors and certifies the coating prevents rust and corrosion

By coating the cooling vanes on Element3 Coated Rotors, it keeps the vanes clear of rust and corrosion for optimal airflow and cooling.

Our rotors meet the SAE standard for tensile strength, providing structural integrity and maximum service life.

A non-directional ground finish provides a product that is ready to install right out of the box

Wagner Premium Brake rotors

Premium Wagner® Brake rotors are engineered for maximum performance with an E-Shield® protective electro-coating applied to all non-braking surfaces. This black-colored coating prevents corrosion, makes removal for service fast and simple, and is visually attractive for open-spoke wheels. A turned, smooth surface finish aids in the proper seating of the friction and requires less time for rotor “break-in”.

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Posted on by Rick Muscoplat


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