A tire inflator having an air compressor to inflate a tire to a predetermined pressure threshold. A central OBD module plugged into in a vehicle uses a short-range radio to transmit to the inflator the predetermined pressure threshold fit for a vehicle. An OBD vehicle bus reader can obtain a VIN of an associated vehicle model. A predetermined tire pressure threshold memory contains a predetermined look-up table of tire pressure thresholds for models. A processor uses the VIN to identify the vehicle model in the look-up table to select the one of the predetermined tire pressure thresholds including a spare tire pressure threshold. A short-range radio wirelessly transmits the looked-up tire pressure threshold including a spare tire pressure threshold to each inflator. The tire inflator has an optical moisture sensor on air inlet or air outlet. The air compressor is disabled when moisture is detected.