Never heard this, just experienced it. It's physics, not myth. I once made the mistake of purchasing "lifetime" pads. Never had to replace those pads, but I
sure as hell had to replace my rotors. If you purchase harder pads that themselves wear slower and do nothing with your factory rotors, your rotors will wear faster. You can help offset that by purchasing denser, higher quality rotors. But as I expressed, it is my preference that I keep replacing pads and not bother with the rotors. As far as the potential compromises with heat and going denser, that's why they slot/drill them. The slot/drill also helps with stopping performance and to a lesser degree, rotating mass. But the slot/drill may also increase pad wear.
As the name implies, semi-metallic pads contain anywhere from 30-65% metal by weight, typically consisting of steel, iron, copper, etc. combined with friction modifiers and fillers, as well as a graphite lubricant. Semi-metallic brake pads are arguably the most versatile style available, with the slight compromise being more noise and dust. They are also longer lasting and more durable, and their metallic composition can help draw heat away from the rotor and aid in more efficient brake cooling.
Pros
ramatically increased braking performance over organic padsHave a much higher thermal threshold due to metallic contentStill provide good cold biteHave a much wider operating range (temperature)Low compressibility ā will provide a firmer brake pedal feelMuch more resistant to brake fade than organic padsNumerous compounds available ā suitable for anything from daily street driving to extreme track useCons:Tend to be noisier than organic or ceramic padsProduce more brake dustMore abrasive than other types of pads ā will wear brake rotors more quicklyMore expensive than organic pads (but generally cheaper than ceramic)Require careful and proper bedding-in for best performance
Ceramic Brake Pads
The comparative new kid on the block is the ceramic brake pad. Ceramic pads are composed of a dense ceramic material (like pottery fired in a kiln) with embedded copper fibers. In use since the 1980s, ceramic pads were developed as an alternative replacement for organic and semi-metallic brake pads because at the time these types produced too much noise and dust. Ceramic pads are also generally easier on rotors than semi-metallic pads.
Pros:Quieter than semi-metallic pads ā emit noises that are above the range of human hearingProduce finer, lighter-colored brake dust which does not stick to wheelsLonger lifespan than organic or semi-metallicStable under a wide range of temperatures for consistent performanceCons:Typically the most-expensive type of brake padDo not produce as much cold bite as semi-metallic pads ā may not be ideal in extremely cold climatesDo not absorb heat as well as semi-metallic pads which can increase brake system temperaturesGood all-around braking characteristics but were never designed as heavy duty/racing brake padsBraking is a Compromise
Back to the question at hand - semi-metallic vs. ceramic brake pads. As said before, there is no single brake pad that can reign supreme in every single situation. If you want clean, quiet stops, youāll pay for it in braking performance. If you want massive amounts of brake bite under extreme temperatures, youāll be cleaning your wheels every few days. Thatās just the way it works in the world of brakes. Ceramic pads offer quieter stops, cleaner wheels, and generally longer pad life due to their harder composition. The downsides include less cold bite, rendering them less effective in cold weather or before the brakes are up to temperature. In addition, they typically have a lower coefficient of friction than their semi-metallic counterparts (the higher the coefficient of friction, the better a brake pad will stop your vehicle). Ceramic pads were never designed to be extreme performance or racing brake pads. The ceramic material is also a less-effective heat sink than their metallic equivalents - instead they act almost like an insulator. The less heat the pad is able to absorb, the more the heat is retained in the brake rotor and surrounding components, which can lead to increased temperatures of the entire brake system.
Semi-metallic pads, on the other hand, while they do produce more noise and dust, are arguably the more versatile of the two. They are more effective over a wider range of temperatures and have a much higher thermal threshold. They provide better cold bite than ceramic pads and maintain much more consistent friction characteristics throughout their operating range. If you plan on driving your car in anger on a racetrack (or even a spirited mountain run), semi-metallic pads are the clear choice. But for casual city or highway driving, commuting, or chauffeuring the kids around town, ceramic or organic pads offer ample stopping power with the added benefits of quietness, cleaner wheels, and longer lifespan.
Read it an weep...you have been sacked....misinformed....led astray or other wise fooled my fellow mate....
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