Abstract: An apparatus is capable of determining inflation pressure of a pneumatic tire mounted on the wheel of a vehicle, the tire being in contact with a support over a contact area. The apparatus comprises: (i) sensing means comprising one or more sensors within said support, each sensor being adapted to measure the average contact pressure over the sensor between said tire and said support, and each having a surface area less than the said contact area; and (ii) processing means adapted to determine an average contact pressure between said tire and said support from an output of only a sensor or sensors which fall entirely within said contact area so as to provide a measure of the inflation pressure of the tire to a first order of accuracy. A corresponding method is also disclosed.