New Moto Guzzi Door Mats Available Now
Unless you are moving at the glacial pace you only lose a little burp of air (using a screw on type ) or not enough to effect the overall level of inflation. The DynaPump does have an air test port so you can take a pressure reading while everything is connected. If you are really that worried about nailing the pressure over inflate the tire by 1 PSI and then disconnect. If you are using a $2 stick gauge also be advised their accuracy will rival the accuracy of 70's ere Veglia speedo/tachometers.