- Engine power (speed): A car's power allows it to reach higher speeds in less time. Braking from high speeds generates exponentially more heat than braking from low speeds. For example, braking at 200 km/h produces four times more thermal energy than braking at 100 km/h (since kinetic energy is proportional to the square of the velocity). This requires pads with a stable coefficient of friction at very high temperature ranges and excellent fade resistance.
In summary, a heavier and/or more powerful car will generate many times more heat and force than a lighter or less powerful vehicle. Ignoring these factors when choosing your sports brake pads is a common mistake that can lead to subpar performance.
- Engine power (speed): A car's power enables it to reach higher speeds in less time. Braking from high speeds produces exponentially more heat than braking from low speeds. For example, braking at 200 km/h generates four times more thermal energy than braking at 100 km/h (since kinetic energy is proportional to the square of velocity). This demands pads with a stable coefficient of friction at very high temperature ranges and excellent fade resistance.
In summary, a heavier and/or more powerful car will generate many times more heat and force than a lighter or less powerful vehicle. Ignoring these factors when choosing your sports brake pads is a common mistake that can lead to poor performance, premature wear, or, worse, safety risks due to loss of braking capacity.
What technical factors should you consider when choosing sports pads?
Once you understand the load imposed by weight and power, it is essential to know the key technical characteristics of sports brake pads that determine their performance and suitability for each vehicle.
Coefficient of friction
The coefficient of friction (µ) measures the ability of the pad to generate grip against the disc.
- High coefficient: Means the pad has a lot of "bite." It generates significant braking force with less pressure on the pedal. This is desirable in powerful and heavy cars that need to dissipate a lot of energy. However, an excessively high coefficient can make modulation difficult and cause overly aggressive braking in lighter cars or for daily use.
- Coefficient stability: It is crucial that the coefficient of friction remains stable across a wide temperature range, especially as the pad heats up. Poor-quality pads lose grip at high temperatures, causing the dreaded fade.
Operating Temperature
Each brake pad compound is designed to operate effectively within an optimal temperature range.
- Minimum/Initial Temperature: The temperature at which the pad begins to perform adequately. Pure competition pads usually require a high minimum temperature (above 200-300°C) to be effective.
- Maximum Operating Temperature: The temperature at which the pad can function consistently without losing its properties (fade). For high-performance sports brake pads used for mixed purposes (street/track day), this range can go up to 600-700°C. For racing, pads that exceed 800-900°C are sought. Choosing a pad that does not reach its minimum temperature during your usual use will result in ineffective braking, while one that overheats above its maximum will suffer from fade.
Wear and Durability
Pad and disc wear, as well as durability, are interconnected factors that are often inversely proportional to the coefficient of friction and heat resistance.
- Pad wear: The most aggressive and high-temperature resistant compounds tend to wear out faster.
- Disc wear: Some harder pad compounds can accelerate the wear of brake discs. It's a compromise.
- Durability: For sporty street use, a good lifespan is desired without sacrificing too much performance. For racing, durability is sacrificed in favor of maximum efficiency and fade resistance in a very short cycle of use.
The ideal combination of these factors will depend on the specific use of your car and its weight and power characteristics.