The interaction between tire and road is crucial for determining the vehicle’s dynamic behavior. In particular, during motion, the vertical load exerted at the tire-road contact point is a key variable to be accounted for in designing active control systems both for traction and braking. In this work, we propose an innovative method for estimating road-tire contact forces based on the measurement of both standard vehicle sensors – i.e., wheel encoders – and of a high-performance accelerometer mounted directly in the tire. The in-tire accelerometer signal is acquired via a radio-based telemetry system, connected to a standard dSpace based acquisition system. We will show how to derive from these measurements an estimate of instantaneous vertical load and of tire contact patch length. The work is based on experimental data, collected by an instrumented car.