The simulation of the brake disc temperature is an important tool in the development of passenger cars. Nowadays thermal models of brake discs are real-time applications, running on electronic control units (ECUs) of cars to improve the vehicle safety in several ways. These models are often working with full empirical methods, leading to large deviations between calculation and measurement. To meet the requirements of automotive safety integrity levels (ASILs), these thermal models cannot rely on the state of the art ambient air temperature sensors, which causes unacceptable deviations. Focusing on numerical efficient thermal simulations, a new approach of a semi-analytical thermal network for simulating the brake disc temperature with minimal effort is proposed. The thermal network is based on lumped parameters, using two thermal capacity nodes and a constant ambient temperature. Using semi-analytical correlations, the model can be adapted to different geometries and car lines effortlessly. The empirical parameters of the model result only from two standardized tests. These parameters are used to evaluate the estimation accuracy in real driving situations. Additionally, the adaptability is tested for two different car lines and four brake disc dimensions. These tests are initially performed with unchanged parameters and afterwards with refitted parameters. The model shows a good estimation for the tested load cases. Compared to the state of the art, the proposed model is less accurate than complex finite element method (FEM) models and computational fluid dynamic (CFD) approaches, but shows a higher accuracy and better adaptability than other lumped parameter models with comparable numerical effort. Hence, possible applications can be dimensioning the brake system in the development process of new car lines or a real-time simulation on the latest ECU in the vehicle.Corresponding author: Manuel Arnold, M.Sc., research fields: mechanical engineering, temperature models, safety functions. simulation is used for calculating the friction power.