The Xiaomi SU7 Ultra is set to be released at 7 pm on October 29. On October 28, Xiaomi officially announced that the mass-production version of the Xiaomi SU7 Ultra would be equipped with the largest racing-grade carbon-ceramic brake disc in a sports car, with a maximum operating temperature exceeding 1300°C.
Most brake discs used in cars today are made of metal. Although they perform well, they still fall short compared to carbon-ceramic brake discs. This technology was reportedly first used in aircraft in the 1970s and in race cars in the 1980s. The Porsche 996GT2 was the first civilian car to utilize carbon-ceramic brakes. A car equipped with this braking technology is said to be able to go from 200 km/h to a complete stop in just three seconds. However, due to the extremely high performance of this technology, it is rarely seen in civilian vehicles and is typically found in sports cars worth over a million dollars.
Carbon-ceramic brake discs are a friction material made using carbon fiber as a reinforcement. This takes full advantage of carbon fiber's properties, including high strength, low density, high-temperature resistance, fast thermal conductivity, high modulus, friction resistance, energy efficiency, and environmental friendliness. Notably, the dynamic friction coefficient of carbon fiber composite friction material is significantly higher than its static friction coefficient, making it one of the highest-performing friction materials available.
The primary advantage of using carbon-ceramic brake discs is that they resist cracking, thermal expansion, and brake fade. Moreover, at high temperatures above 200°C, these common issues are mitigated, and the friction coefficient actually increases, meaning that on steep slopes, the brake performance improves with prolonged use. Additionally, carbon-ceramic brake discs do not rust, have excellent corrosion resistance, and typically last between 80,000 and 120,000 kilometers. Compared to standard brake discs, they offer nearly every advantage, with the exception of high cost.
Lei Jun has described the mass-production version of the Xiaomi SU7 Ultra as "his dream car." Combining "peak performance, cutting-edge technology, and the ultimate driving experience," the Xiaomi SU7 Ultra is designed to be "street-racable," capable of speeding on the track and cruising through the streets.