An on-board centralized system for regulating pressure of tyres of a vehicle includes a pressurized air source, a circuit communicating the source with a plenum of each wheel, and an arrangement for connecting the plenum of each wheel to the inner chamber of the respective tyre that includes first and second connection lines for deflation and inflation, respectively, of the tyre, and first and second one-way valves interposed, respectively, in the first and second connection lines to allow only a flow of air respectively from and to the inner chamber. The first valve includes a spring having a pre-set load so as to isolate the inner chamber from a part of the circuit upstream of the first valve when said upstream part is at atmospheric pressure, and to guarantee a pre-set minimum value of pressure in the inner chamber when the upstream part is at a pressure lower than atmospheric pressure.