quote:Originally posted by JamesM:
I am interested in how you measure the pressure in a high pressure tube, something like a 19mm road tube that has 90 to 100 psi, without releasing any of the pressure.
When ever I attempt to check the pressure using a press on gauge or a bike pump gauge there is some air lost.
Air loss is nearly always the case unless you use an appropriate commercial gauge with good technique. At a trials validation, Pete Riegel gave up on correlating performance with tire pressure because of the problem. However, I spent a lot of time in developing gauges that screw onto valve stems without ever losing air(Measurement News 131). Note that I keep the gauge attached to the stem throughout the certification measurement.