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Brake Terminology, Technical and Trends Hi Guy's, I have a favourite saying "No matter how much you polish a turd, its still a turd". I've been away from the brake industry for a while but some things never change. The polishing of products to convince people to buy. I thought it might be a good idea to share some technical terms and some of the science behind brakes so you can compare apples for apples as they truely are behind the glossy marketing and verbal diarrhea. I have no intention of naming or bagging out any brands or manufacturers (unless they piss me off) so lets keep it clean and educational. Brake Pads I’ve been fortunate enough to have been factory trained with a couple of friction lining manufacturers around the world. NAO, Sintered metal, carbon metallic and low metal high carbon pads. One thing is for sure, its personal. Every driver has a different perception of what is good braking. Why we have so many arguments ;-) The most basic of identifiers for brake lining characteristics is the good old SAE J661 hot and normal (cold) friction coefficient test which is the codes stamped on the pad backing plate. They will look like; EF, FF, GF, GG etc printed in between a whole heap of numbers. The other numbers refer to batch codes and friction formula used. The USA and Europe require this detail to be marked on the pads to comply to various legislations. SAE J661 - Friction identifiers. Normal Friction , Hot Friction is the order of the codes E = 0.25 to 0.35 mu F = 0.35 to 0.45 mu G = 0.45 to 0.55 mu H = 0.55 and above The USA (mainly Ca and Wa) have introduced a hazardous materials legislation called Chapter 70.285 RCW which I have had the joy of participating in for compliance. They've identified a number of ingredients in brake linings that are polluting water ways and making their fish glow in the dark. Copper reductions is a major topic in the USA as this is one of the main offenders. As with the bans on asbestos many years ago, the same appears to be happening with Copper. Another topic is the European R90 compliance. Its been around for a long while but is gaining more focus locally. Possibly because sales guys have run out of things to talk about. R90 is all about driving comfort. NHV (Noise, Vibration, Harshness) is the focus. This is directed towards regular road pads of which most OEM's are compliant and aftermarket no so much. Key metrics for measuring performance; I'll add some more detail about these soon. Torque response (initial bite) Peak effectiveness (peak friction @ time/temp/pressure) Release speed (speed to fully retract) Modulation factor (compressibility and a combo of above) Pad wear A good driver will understand these metrics and will be able to adjust his methods to suit in order to achieve the desired outcome whether it be sprints, endurance, off road, or just regular road driving. I hope this terminology helps. Please feel free to ask any questions. No such thing as a dumb question. Cheers DBASteve