Composite brake rotors?

[92saturnsl2]

On Rockauto, one of my vehicles lists "composite" brake rotors as an option for the front and rear rotors. The picture looks like an ordinary rotor. Are there any benefits to the composite one, the price is near equal. Others mention "black e-coat, replaces OE composite design." What gives?

 

[rubberchicken]

Yes , there is a difference. The composite term requires clarification: My 1997 2500 Suburban had composite rotors, but it was explained to me by my Chevy mechanic friend that the rotor face was one type of iron / steel, while the hub was a different type of iron. This made them work better / longer in trucks. 2 different materials qualifies the item as "composite", although we normally think of something like carbon fiber when the term is used. The price difference was huge- about $200 for the OEM rotor, and around $50 for aftermarket non-composite rotors. Supposedly the composite rotors could only be turned if you had a special brake cutting machine that could handle composite rotors. My brother was an aerospace engineer that specializes in composite materials and he verified that the term was technically correct but sort of misleading. If there is only a slight difference, get the composite rotor as that matches the OEM design. If its a huge difference, then I leave it up to you.

 

[Audios]

Usually my local suppliers call composite rotors ones with different hats, like these from my E46 M3 https://www.turnermotorsport.com/p-1518-cross-drilled-floating-brake-rotors-front-e46-m3-cslzcp/

 

[maxdustington]

Originally Posted by 92saturnsl2
On Rockauto, one of my vehicles lists "composite" brake rotors as an option for the front and rear rotors. The picture looks like an ordinary rotor. Are there any benefits to the composite one, the price is near equal. Others mention "black e-coat, replaces OE composite design." What gives?
Sounds like a standard, coated rotor that is a replacement for a factory composite.
Originally Posted by Audios
Usually my local suppliers call composite rotors ones with different hats, like these from my E46 M3 https://www.turnermotorsport.com/p-1518-cross-drilled-floating-brake-rotors-front-e46-m3-cslzcp/
That's what I was thinking of: rotors where the friction part is separate from the hub part. I guess it's easier or cheaper if you car eats rotors on a racetrack to get those composite rotors.

 

[Audios]

Its mostly for weight and heat dissipation, these come on newer 5/6/7 series and you can get them either composite or all carbon steel like from ZImmerman, no real difference to justify the crazy cost.

 

[DoubleWasp]

GM pioneered the "dual cast" brake rotor, where you either get an iron rotor with a steel hat, or an iron rotor with aluminum hat.