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Views: 0 Author: Site Editor Publish Time: 2025-09-17 Origin: Site
Stopping distance is a core indicator of vehicle braking safety. As the component that directly generates friction, differences in brake pad performance directly impact stopping distance. Brake pads of varying materials and designs have distinct characteristics in terms of friction coefficient, high-temperature resistance, and compatibility with the brake disc/drum, ultimately affecting the distance a vehicle takes to stop from braking.
The material of the brake pad is a key factor affecting the friction coefficient, which directly affects the amount of braking force. Under the same vehicle conditions, a higher friction coefficient generates greater friction per unit time and shortens the stopping distance. Currently, mainstream brake pad materials fall into three categories, each with significant differences in their impact on stopping distance:
(1) Resin-Based Brake Pads (Semi-Metallic/Low-Metal): The "Balanced Choice" for Family Cars
Material Composition: Resin is used as a binder, mixed with a small amount of metal fibers (such as steel and copper, accounting for 20%-30%) and friction modifiers. These are currently the mainstream materials for family sedans and urban SUVs.
Friction coefficient: Approximately 0.35-0.45 at room temperature, which is considered medium.
Impact on braking distance:
Daily urban driving (speeds under 60 km/h): Braking distance is moderate, approximately 15-20 meters from braking to stopping, sufficient for most commuting needs.
High temperatures or continuous braking (such as downhill on a mountain road): Thermal decay is likely to occur above 300°C, and the friction coefficient may decrease by 15%-20%, resulting in longer braking distances (e.g., at 100 km/h, the vehicle may slide 5-8 meters longer than at room temperature).
Suitable for: Family cars primarily used in urban areas with occasional highway travel, offering a balance between braking performance and durability.
Material composition: Based on ceramic fibers and mineral fibers, free of metal particles, and containing a high-temperature friction agent, these pads are commonly found in mid- to high-end models or vehicles with demanding braking performance.
Friction coefficient: Approximately 0.4-0.5 at room temperature, maintaining a coefficient of 0.38-0.45 at high temperatures (above 600°C), with minimal thermal degradation.
Impact on braking distance:
On dry roads (100 km/h): Braking distance is 3-5 meters shorter than resin-based brake pads (approximately 35-40 meters, resin-based approximately 38-45 meters).
Continuous braking scenarios (such as long downhill slopes and frequent hard braking): Due to its strong thermal stability, braking distance is barely noticeably increased, while resin-based brake pads may experience an additional 8-10 meters of slip due to thermal degradation.
Advantages: Suitable for mountainous roads, long-distance highways, or vehicles frequently laden with vehicles, maintaining stable short-distance braking under harsh conditions.
(3) Metal-based brake pads (all-metal): The "aggressive choice" for performance vehicles
Material composition: Contains metal content exceeding 50% (cast iron, steel fiber, etc.), resulting in a high coefficient of friction. Commonly used in racing cars, performance vehicles, and heavy-duty vehicles.
Friction coefficient: Can reach 0.5-0.6 at room temperature, providing extremely strong braking force.
Impact on stopping distance:
At a speed of 100 km/h, braking distance on dry roads can be reduced to 30-35 meters, 5-8 meters shorter than ceramic brake pads, making them suitable for situations requiring instant braking (such as overtaking on a racetrack or emergency evasive maneuvers).
Limitations: Severe wear on the brake disc/drum (high metal hardness), prone to "squeaking" at low temperatures, and large fluctuations in the friction coefficient on slippery roads (potentially increasing braking distance due to slippage), making them unsuitable for daily use in family cars.
Brake pads do not work in isolation. Their interaction with the brake disc (disc brakes) or drum (drum brakes) further affects stopping distance:
In disc brakes, the brake pads press against the brake disc through the caliper to generate friction, making the smoothness and fit of the contact surface crucial.
Brake pads made of too hard a material (such as inferior metal) will accelerate brake disc wear, leading to grooves and deformation on the disc surface. This reduces the contact area between the pad and the disc, reducing friction and increasing braking distance (possibly by 10%-15%).
High-quality ceramic brake pads or compatible resin-based brake pads provide a more uniform friction surface with the disc, consistently maintaining maximum contact area and ensuring consistent braking distance.
Drum brakes are commonly found on the rear wheels of trucks and low-end cars. The brake pads are mounted inside the drum and apply brake force by expanding and rubbing against the drum's inner wall.
Uneven brake pad wear (e.g., thicker on one side and thinner on the other) can lead to a loose fit with the drum's inner wall, unbalanced braking force distribution, and increased braking distance (especially under heavy loads, potentially resulting in over 10 meters of slippage).
Furthermore, brake drum deformation due to high temperatures can exacerbate abnormal brake pad wear, creating a "vicious cycle" that further increases braking distance.
A brand new brake pad is approximately 10-15mm thick. When worn below 3mm, the friction area decreases, significantly reducing braking force. For example, at 60km/h, a brake pad at the end of its wear cycle may have a stopping distance 5-8 meters longer than a new pad (from 15 meters to 20-23 meters), requiring prompt replacement.
Low temperatures (e.g., winter temperatures below -10°C): Resin-based brake pads may experience a 5%-10% decrease in friction coefficient, slightly increasing stopping distance. Ceramic brake pads are less affected by low temperatures and offer more stable performance.
Rain, snow, and slippery roads: The friction coefficient of all brake pad materials decreases (approximately 20%-30%). Braking distance in this situation depends primarily on tire grip, but high-quality brake pads (such as ceramic pads) offer greater resistance to water fade and can achieve a 3-5 meter reduction compared to lower-quality pads. 3. Braking Frequency
Repeated hard braking (such as following a vehicle in congested traffic): Resin-based brake pads are prone to thermal degradation due to high temperatures, resulting in increased braking distance (30 meters for the first stop, up to 35 meters for the third stop). Ceramic brake pads offer excellent thermal stability, with a distance change of no more than 2 meters after repeated braking.
Daily commuting in a family car: Prefer resin-based or entry-level ceramic brake pads with a friction coefficient of 0.4-0.45 to balance stopping distance and economy.
Frequent mountain and highway driving: Choose ceramic brake pads with a friction coefficient of 0.45-0.5 to cope with high temperatures and continuous braking, thus minimizing the increase in stopping distance.
Performance vehicles and modified vehicles: Metal-based brake pads can be used, but they must be paired with high-strength brake discs and tolerate the high wear and tear they cause to components.
Trucks and heavy-duty vehicles: Choose specialized heavy-duty brake pads compatible with brake drums to ensure even wear and avoid excessive stopping distances due to insufficient braking force.
The impact of different brake pads on stopping distance hinges on the friction coefficient and high-temperature resistance, determined by the material. Ceramic brake pads offer the shortest stopping distance in most scenarios, especially in high-temperature environments. Resin-based brake pads are suitable for everyday use, offering moderate stopping distances. Metal-based brake pads offer a significant advantage in short distances, but their applicability is limited. Furthermore, the compatibility of the brake pad with the brake disc/drum, its wear state, and the operating environment can further exacerbate these differences. Choosing a brake pad requires comprehensive consideration of the vehicle type and road conditions to achieve the optimal balance between safety and practicality.If you are looking for a safe and durable brake pads,please contact us:+86-13363216781,or email us:jessicabrakes12@gmail.com.Our website address is https://www.evfriction.com.
