Brake Pads - what you need to know - friciton codes

[AuburnRyan]

After many years of being an enthusiast and researching/buying different sets of pads - I've stumbled upon new information to me anyways, that I'd like to share to help other out.

All DOT approved pads have friction codes a.k.a edge codes that would help one to understand their performance characteristics. This would help us all understand how pads are baselined, rather than having to rely solely on variables and "opinions" of other users. Lets call them cold bite and warm bite (friction or torque).

The scale is E-H, with E representing no or little friction or bite in comparison to H, with more bite or higher coefficient of friction.


Some cut/paste info:

This two letter edge code mandated by the DOT, and painted on all street legal brake pads, will give you some indication of their ability to bite and resist fade, because of the wide range involved in each letter, it is only a rough indication.
Explanation of D.O.T. Edge Codes Located on all Brake Pads 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
EF 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

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!! (I just looked up steel friction coefficients online appears to be .6 - but whatever) 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.

I also noted in online research that "European" pads are usually F-H rated, probably why they give that great braking performance at the expense of dust.

Most popular street pads I can find info on are EE rated..but it's hard to find this information as oddly it's not widely distributed - though required by DOT to be on the pad.

So my suggestion is to get a list going of pads you have, and their friction code to help us all be (more) educated when choosing pads.

HAWK HPS = FF
HAWK HP+ = GG
Axxis ULTIMATE = FF
Ferodo DS2500 = FF
EBC 6000 Series Organic = GG

[Moron95M3]

very good info!

[das borgen]

now I understand the meaning of the EBC HH pads on my motorcycle

thanks! OP

[AuburnRyan]

ECE-R90 Certified Pads have E11 printed on the pads - it's European standard meaning - Both the Original Equipment Brake Pads and the Aftermarket Pads are tested and undergo simulated braking with the performance, fade and recover characteristics recorded. Only if the Aftermarket pads perform to +/- 15% of the Original Equipment parts will the pads be eligible for certification.

I assume then that pads that outperform the stock pads by 15% will not qualify...so it's not a sign that all "good" pads must have this - when you're upgrading for example, but perhaps a good sign the pads will perform like stock and are of "good" quality.

[breakfast]

wow that is awesome...and definitely correlates to what ive known....2500/ultimates and hps are very similar.

[jeffdedecker]

I'd like to add to AuburnRyan's list even though its been a few years. I found friction ratings hard to find online within any forum; therefore, here is the research I've collected at various parts stores (Jan. 2016), including some OEM that I wanted as a reference point.

Duralast Gold - FE Duralast Max - FF Nissan Ceramic - FF Toyota Ceramic - FG Akebono ProAct Ceramic- FG Wagner ThermoQuiet Semi-Met - FG Wagner ThermoQuiet Ceramic- GG Akebono Performance Ceramic - GG Performance Friction Carbon Metallic - GG

My only experience at this time is with the P.F. Carbon Metallic. They last a long time, but they need to be warmed up. I was happy with them until I needed to stop quickly within the 1st mile of my drive.