Brake Horsepower

Is a method of rating engines whereby the power required to stop them defines the engine's strength. A measure of the power of a braking system would be pointless as it would depend on the vehicle, tires and road conditions. In other words, if the brake (caliper/disk assembly etc.) from a motorcycle was able to lock the wheels of the bike, then made capable of locking up the wheels of a semi-trailer it wouldn't stop the bike any faster.

For industrial brakes, rating is usually in torque resistance and heat dissapation. Two factors relate to braking effectiveness, how much resisting torque a brake can apply and how fast the heat can be removed. I recall some PBS episode on large aircraft testing. The final test shown was a jumbo jet being landed at gross weight with maximum braking. The brakes were so hot, all tire blew out sitting on the runway. The objective was to stop the plane yet not catch fire for 15 minutes. After 15 minutes, the landing gear was doused with water to be safe!

First one must understand the information being offered for it to be concidered useful. The laws of physics are not, per say, tied down to anything hardlined, or better, in black and white as a justice law. The laws of physics are binder rules which are subject to change at any moment when their properties are defined and subject matter results are brought forward in cleaner form for others to understand in a simpler and more concise answer. For your braking information of not having useful information, you need to grasp a more concise understanding in the terms developed, that depick the actual functions in relative terms, of the process. Like converting metric terms to ASE terms. That is undstood as "American Standard Engineering" terms. Or otherwise simplified descriptors of the process. We have derived, in simpler terms of process functions, such as "pounds per inch", which can be used in many terms. Because this simple phrase has several grey areas in its' usage. There can be several functions termed with this stadard phrase. Is it "pounds per inch" in pressure, in distance, such as tensil strength of a material being stretched. Is it "pounds per inch" such as force being applied when one is tightning a bolt to a specific reference. So as far as useful information, one will actually need to have a clear understanding of force applied to the function, the materials used with the function, the type of mechanical instruments to applie the force and to measure the force/ results of the function. The composition of other materials used as a comparrison from one to another in the process of elimination, garnering the best materials used for the best results in the functions applied. Have I lost you yet in the actual process that is being used to gather the non-useful information supplied with brake pads from the manufacture? It is all in the way things are done to meet specified requirements from laws that have been put in place for disclosure of materials and the ingredience of any said product offered to the general public, for you protection. Sorry for the soapbox explenation, but you asked for it. Good luck in your quest.

I have some small understanding of Braking systems. Discs are better than drums, large discs are better than small ones, for calipers larger pads & more pistons are better... Tires are of course important, lots of factors to consider. The braking system turns kinetic energy into heat, the effectivness of the system is in part determined by how fast the heat generated can be dissipated to keep the pads [ shoes ] @ optinum temperature, the other part being how well the tires stick to the road [ surface ]. Reading any sort of "Motorhead" publication or manufacturer litrature, brakes are described not quantifed! Maybe brake horsepower wouldn't be ths proper unit of measure...

There is a lot of rubbish written about brakes. First of all, don't worry about ratings on any particular set up. The capability to stop efficiently depends on a great many factors. In the real world, however, this is what you need to know. You will not stop any quicker then your tyres allow. Make sure you have good quality tyres. (This affects your ability to stop more then any other factor, if your tyres are locking up, you're not slowing down.) Cooling is the next factor you need to consider. Drum brakes are more efficient then disc brakes, right up to the moment they get hot. They are unable to dissipate heat as quickly as discs. That being said, getting cool air to your discs is only half the battle. You also have to get rid of the hot air. Consider the use to which you put the vehicle. If it's for every day road use and you want to up rate the brakes for better 'feel' and stopping power, replace the pads with a specific grade, for example, I use EBC green stuff on the road, and red stuff on the track (check out the EBC web site. Also - AP Lockheed- Ferodo etc.) These are designed to operate at higher temperature then standard pads, but you must check out the compatibility with you're brake discs. (I usually use standard size after-market discs) Some discs wear badly if you use sintered pads. Also remember that a higher temperature rated pad won't work as well when cold. If using on the road, don't go charging up the lights at the bottom of you're street first thing everyday and expect to stop, they take a little while to warm up. Temperature again! Don't just go out and get the biggest set of callipers you can fit in your wheel. This will block the air flow, and unless you've spent a lot of money on lightweight items, you can upset the suspension due to a higher un-sprung weight. If this is too much information, just remember this simple rule – brakes work because of friction, friction = heat - too much heat = no brakes - Brake manufacturers are salesmen. One more thing, if you are not completely confident of what you are doing, don't do it. Brake failure can be fatal.

In the 80's I was racing enduros & harescrambles in Louisiana. in the mud brakes were, sort of an after thought. You would steer w/your hips & feet, pitch it sideways to blow off speed & try not to hi-side, look for trees & berms to change direction. I was just sort of pondering why there's so much info about getting up to speed & so little [ comparativly ] about slowing down. Thanks for all the great replies