Notes: These edge codes are located on the edge of the friction material of every brake pad by government regulation, along with some other codes. The first letter is a grading of the C.F. at 250 F and the second letter is a grading of the material at 600 F. Each letter grade can actually have quite a range of C.F. But a difference in the letter grade from medium to hot temperature could be an indicator of fade. The letters can be in any order. Therefore FE pads fade when hot, and EF pads would not grab when cold.. Also, you should know that Steel on Steel has a C.F. of 0.25!! So EE pads have only marginally more torque than no pads at all! Therefore FF pads are usually considered the minimum for a high-performance pad.
Pads with many different compositions will have the same edge code.
Official D.O.T. Edge Code
Coefficient of Friction (C.F.)
@ 250 F and @ 600 F
Comments
EE
0.25 to 0.35 both temps
0-25% fade at 600 F possible
FE
0.25 to 0.35 @ 250 F
0.35 to 0.45 @ 600 F
2% to 44% fade at 600 F possible
FF
0.35 to 0.45 both temps
0-22% fade at 600 F possible
GG
0.45 to 0.55
Very Rare
HH
0.55 to 0.65
Carbon/Carbon only.
O.K. up to 3000 F where it glows
most common brake pads have a mixtures of components,
Fibers of varous sorts, you can have fiberglass, Kevlar, steel, copper, etc. Used to have asbestos, but no more. There is the friction material can be anything from clays, metal powders, various grades of ceramics, all embedded in some kind of thermosetting resins. There are also wear additives such as carbons, graphites, copper, plastics and quieting agents. It is actually way more sophisticated that simply ceramic, or what the edge code indicate.
