Brake Rotors - Part 1

[RichardNew]

This week it's all about brake rotors. Part 2 will appear near the end of the week.



Richard Newton
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[RWebb]

you could explain that red mark on the rim...

[RichardNew]

I'm not sure which red mark (or which rim) you're talking about?

Richard

[motogman]

Richard's articles are usually interesting and stimulate some discussion and debate.

In this article it is stated: "Cheap rotors are made from damped steel. "

Automotive rotors are not made of steel... they are made of cast iron which has much better thermal transport properties and is cheaper. There are different grades of grey iron and one is indeed called damped iron. It is sometimes used in OEM rotors to manage brake noise issues. Some motorcycle and other ATV vehicles rotors are made from steel or stainless for cosmetic reasons.

While it is true that most of the aftermarket rotors are foreign sourced, there are still many OEM rotors for US production made in the US.

Relative to two piece rotors, as stated there is potential weight savings (at the cost of complexity) but a big advantage of two piece (pined or floating) rotors is reduced stress in the rotor and less distortion as it is allowed to expand radially with heating where a one piece rotor is constrained and hence typically has higher stress and potential for cracking.

[RWebb]

Originally Posted by RichardNew

I'm not sure which red mark (or which rim) you're talking about?

Richard

pic above

[RichardNew]

Ok, I know now what you're talking about. The Red Mark.

It's a temperature sensing paint. The paint changes colors as the rotor reaches certain temperatures. This is used on race cars and track cars. You can put the paint on the rotor before you go out on the track. Performance Friction also likes it on the top of the brake pads themselves.

The there thing is you might consider putting a temperature strip on the caliper itself. You should probably use both.

I may run about 1200 degrees at the rotor but only 400 degrees on the caliper. There's that much difference.

Richard Newton

[RichardNew]

Here's the best thing to use on a caliper. These come in various heat ranges. You're probably going to be at about 400 degrees. At least you hope you are. Try and get a strip with 400 in the middle.



If you're running 2-piece rotors you might want to put one on the top hat as well. That's in addition to the paint on the rotor itself.

There is no such thing as too much information.

Richard Newton

[RichardNew]

Here's Part 2.

Richard Newton