The knowledge of the forces acting between tire and road is crucial for modern vehicle control systems. Typically, such forces are estimated on the basis of indirect measurements and rely on complex mathematical models. Sensors embedded in the tire (e.g. accelerometers) offer the possibility of directly reaching the area of the tire-road interaction, and of delivering signals during the wheel rotation. Such signals reflect the tire state and the force exchanged between tire and road. In this paper an innovative approach to estimate such forces is presented. It exploits the signal delivered during the wheel rotation by an accelerometer glued to the inner side of the tire tread. The approach consists in processing the signal by means of the Principal Component Analysis (PCA). The results of experimental activities employing a real vehicle provide evidence to support the feasibility and the soundness of the proposed approach.