Temperature Measurement of Brake Discs for Optimizing Safety and Performance

Challenges in Measuring the Temperature of Brake Discs Under Extreme Loads

The thermal resistance of a brake disc is critical to the performance, safety, and service life of modern braking systems. Particularly in high-performance road vehicles, motorcycles, and motorsports, brake discs must convert large amounts of kinetic energy into heat within a very short time. Manufacturers must design brake discs that operate safely even under extreme loads without making them unnecessarily large or heavy. This requires precise knowledge of the surface temperatures and their distribution across the brake disc.

Thermal requirements vary considerably depending on the material and application. Conventional steel brake discs can reach temperatures of 800 to 900 °C or higher under heavy loads. High-performance brake discs made of ceramics, carbon, or composite materials can reach temperatures of up to 1,200 °C. In some high-performance braking systems, optimal braking performance is only achieved at elevated operating temperatures. Inaccurate temperature measurements can lead to incorrect brake disc design, potentially resulting in overheating, material damage, or a significant reduction in braking performance.
Conventional measurement methods are insufficient for these applications. Estimating temperatures based on the visible glow of a material provides only a rough indication and is not suitable for all materials. Contact thermometers cannot continuously measure temperatures during braking. Integrated thermocouples also require considerable installation effort, as they must be connected to the rotating brake disc through slip rings that are susceptible to wear and failure. Furthermore, point-based measurement methods cannot provide a complete picture of the temperature distribution.
The development and validation of modern braking systems therefore require continuous, non-contact, full-field temperature measurement. Only this approach makes it possible to identify thermally critical areas, evaluate heat dissipation, and optimize brake disc design in terms of safety, performance, and weight.

Improved Brake Disc Design Based on Precise Temperature Data

The main advantage of Optris infrared cameras is their ability to measure temperatures across an entire surface without physical contact. Instead of a single measurement value, engineers obtain a complete thermal image of the visible brake disc surface. This allows them to investigate localized overheating, uneven temperature distributions, and cooling behavior under different load cycles. Radiometric recordings also make it possible to review absolute temperature values and their development over time at a later stage.
Continuous measurement provides comprehensive results more quickly than conventional contact-based methods. Since neither sensors nor slip rings are required on the rotating brake disc, the associated sources of wear and potential failure are eliminated. The compact camera design also simplifies permanent integration into existing test benches. The PI 400i measures just 46 × 56 × 68 to 77 mm, while the PI 1M has dimensions of 46 × 56 × 88 to 129 mm. Both cameras feature an IP67 protection rating, making them suitable for industrial applications.
The recorded temperature data helps manufacturers optimize brake discs in terms of thermal resistance, material usage, and weight. This is particularly important in motorsports, where additional mass affects rotational behavior and unsprung weight. Precise temperature measurement therefore supports the development of lighter brake discs while maintaining the necessary safety margins.
Further optimization is possible by measuring temperatures on both sides of the brake disc, for example, using additional mirrors or a second camera. An Optris air purge collar is also recommended to protect the camera optics from brake dust by reducing deposits on the optical surfaces. For greater automation, optional industrial process interfaces with analog outputs and relay functions can be used. Network connectivity via a USB server with Gigabit Ethernet or integration through the Optris SDK is also possible.
Infrared thermography thus provides a reliable foundation for developing safe, high-performance, and weight-optimized braking systems.