When it comes down to your brakes, friction is a big factor. The friction of your tires against the surface of the road is what causes your vehicle to slow down and stop. What’s more, the power your brakes use to stop must match the power of your car’s engine to propel it forward.
In a disc brake system, brake pads are key components in stopping safely. When you pump the brakes, the brake pads take on most of the direct force. They are made of steel backing plates with friction material that faces the brake rotor. That material changes the kinetic energy of the spinning disc into thermal energy or heat.
For brake pads, the most important factor is the friction coefficient. It’s the ratio of the friction between the brake pads and the rotor and the force that presses them together, which happens when you use your car’s brakes.
How quickly brake pads conduct heat determines how effectively brakes work under certain conditions. For example, repeated hard braking can result in the pads overheating if they can’t discharge the heat fast enough. Brake pad material with high thermal conductivity would be required with this style of braking.
Brake pads are made from a variety of materials that release heat differently. The type you choose for your car will depend on the vehicle you drive as well as your driving habits. Learning about the most common types of brake pads will help you decide which is best for your car.
Non-metallic (organic) brake pads
Non-metallic or organic brake pads are manufactured from composites of glass, rubber, and resins as well as small particles of metal fibers. These flexible composites make non-metallics the softest form of brake pad. They are manufactured and cured to hold up under a high level of heat. Although these pads reduce brake disc wear because of their softness, they don’t last as long as other types.
Because they are so soft, organic pads are suitable only for the most basic daily driving. Their softness and rapid wear also cause a fair amount of brake dust that can cover nearby components.
In the past, non-metallic pads were originally made from asbestos, which easily dissipated heat and had great wear properties. Asbestos brake pads also were cheaper than semi-metallic ones at the time. But as public awareness grew about this material’s health hazards, asbestos was replaced by other compounds.
Non-metallic pads are recommended only for braking systems that undergo very light use. For most driving conditions, a pad with more metal in its composition or a Kevlar-based pad wears longer and needs less frequent replacement.
Semi-metallic brake pads
The majority of today’s cars use semi-metallic brake pads. They are manufactured from a combination of synthetics and metals to produce a primarily metallic hybrid compound bound together with an organic resin. The compound is molded into pre-set shapes and hardened by dry heat for three to five hours to boost durability.
The metal makes these brake pads more heat- and wear-resistant compared to purely non-metallic pads. Sintered steel, graphite, or iron are the metals of choice for these pads because they easily transfer heat. Semi-metallic brake pads extend the life of the brake rotors. They also generate less dust than non-metallic pads, and their durability makes them cost-effective.
One drawback to metal-based brake pads is that they have a lower friction coefficient at cooler temperatures when compared to more pliable synthetic components in these pads’ composition. When these brake pads are cold, you have to apply more pressure to the brakes to get the same braking force. It may take slightly longer for your car to stop.
Another minor drawback is that these brake pads are heavier than either non-metallic or ceramic. Brake pads with a high metal content will weigh more, which can reduce a car’s fuel economy slightly. These pads can also be slightly noisier than either the non-metallic or ceramic ones.
If more metal — up to about 60% — is added to the compound of this brake pad, it works fairly well in heavy braking conditions and can have better longevity than organic brake pads. A compound like this is ideal for performance cars and heavy trucks. These car require significant braking forces to handle high torque loads.
Ceramic brake pads
The most expensive to manufacture, ceramics are top of the line. Because of the expense and performance, they’re often installed in high-end supercars. They have superior thermal conductivity, so they’re optimal for the hard, continuous braking of racing. Ceramic brake pads can also recover from unforgiving use, even in endurance racing.
The ceramic brake pads’ exceptional ability to transfer heat has a con. As with semi-metallic brake pads, they’re slow to warm up to normal operating temperatures. This feature can work against cars used for everyday driving. But ceramic brake pads are quiet and, like semi-metallic pads, they don’t generate much dust. They last longer than other kinds of brake pads, and they extend the life of the rotors, too.
Choosing the best brake pads for your car
Each type of brake pad has benefits and drawbacks. You’ll need to consider your driving conditions when replacing brake pads. For a daily driver, high-temp steel or ceramic brake pads will waste money as your car’s operating temperature will rarely be high enough to reach optimal braking power. If you drive mountain roads or spend time on the track, basic semi-metallic or organic pads may overheat. Then, your braking response time would be uncomfortably long.
No matter which type of brake pads you choose when upgrading or replacing your braking system, be sure to do your research. With the right brake pads, you can match your braking power with your horsepower in a straightforward, cost-effective way.