Ceramic Vs. Bi-metal Brake Pads

Brake pads are the most dynamic and probably important part of your braking system. Changing brake pads is like changing tires; either way, you're changing a crucial friction-performance component that can make or break the associated system. Ceramic and semi-metallic pads tend to cater to two different markets, but that's not something that the parts-counter guy may tell you when you ask for "a good set of pads."

Pad Basics

Most pads on the market use some sort of organic resin to bind together a substrate that both reinforces the resin and provides stopping power. Back in the day, manufacturers used asbestos fibers to reinforce resins. They later switched to a number of non-asbestos metal compounds including iron, steel, copper and nickel. These semi-metallic, or semi-met pads got some company in the form of carbon, Kevlar and aramid fibers, which replaced most or all of the metal to produce a non-asbestos organic pad. Ceramic pads generally use a certain amount of ceramic dust to replace the more traditional NAO compounds.

Dust

The ceramic's light colored dust is its primary virtue as far as most consumers are concerned. The dust that comes off of a ceramic pad is gray or white in color, so it hides better on and behind alloy rims than a black-dust-producing NAO or semi-met. Ceramic dust is usually easier to clean off of the rim than semi-met dust, and it will generally manifest only as a slight dulling of the rim's surface.

Ceramic Enhancement

Ceramic pads are somewhat less prone to squealing and low-speed groan, which may be a factor for some. Not all braking systems exhibit noise under braking, but vibrations snaking through the system and harmonic vibrations in the pads themselves can make some vehicles more prone to noise than others. Ceramic pads were once a high-dollar aftermarket affair, but these days are price-competitive with most decent semi-met pads. So price-wise, you've got a choice. Bear in mind, though, that not all ceramic pads are created equally. High-dollar exotics use solid ceramic pads and ceramic rotors to provide ultimate braking performance and fade resistance. These kinds of pads probably cost more than your car, and they're in an entirely different league than what you'll find at the standard auto parts store.

Semimet Benefits

The semi-met's greater quantity of brake dust and quicker wear happen for a reason. As unbelievable as it may sound, ceramic plates aren't as sturdy as steel ingots. Go ahead; throw a steel bar into your China cabinet and see what happens. Ceramic pads are softer and less resistant to extreme stresses and temperatures than semi-met pads, and won't typically offer the friction level of even a bargain-basement semi-met. Hot wear and fade for a cheap semi-met and a ceramic are about the same, but a high-performance semi-met will blow them both out of the water where performance is concerned. Of course, the high-performance pad will prove louder, dirtier and shorter-lived than its more civilian counterparts; which one you choose depends upon what you're after.

References

• "High PerformanceBrake Systems"; James Walker; 2007
• "Brake Pad Technology"; Marlan Davis; Hot Rod Magazine; March, 2010