a method and system for monitoring and measuring the amount of deflection of a pneumatic tire wherein said monitoring system in the tire detects tire sidewall deflection by measuring the length of the tire contact patch area relative to the total circumference of the tire . the embedded sensor device generates a signal which varies as it passes through the tire contact patch within the tire on a moving vehicle . if the vehicle is moving at a constant speed , the ratio of time which the sensor spends inside the contact patch to the time the sensor spends outside the contact patch is proportional to tire deflection . sensor electrical signals are digitized and counted to determine deflection , tire speed and the number of tire revolutions to improve performance of both the tire and the vehicle .