nlel wrote:
Even being 1.5 PSI under isn't the end of the world, its ok to be 1 to 2 PSI out. Moderate under inflation starts at 2.9 PSI to 7.11 PSI.
Agreed. Though I would say that if one corner drops by a couple of PSI, I can usually start to feel a hint of "something is off" about my car. All -round balanced deflation of a couple of PSI (perhaps due to cold weather) is, perhaps, less obvious - but it does start to become more so if it's any more than that IMO.
Anyway, it was more that I (and others) had said that it was pointless to be particularly concerned at a pressure gauge measuring differences in tenths of a PSI when it was highly unlikely that the equipment would really be calibrated to that level of accuracy and the inherent variations within the system (tyre, valves, temperature, load etc) made concerning yourself with the tiny daily variations that you were reporting pointless too. And now you now have two different pieces of equipment that vary in their readings under the same conditions by far more than the variations you were initially reporting.
Correct tyre pressures are most certainly important and both under and over inflation can have serious consequences - I'm not denying that - but there is no point worrying about variations of fractions of PSI from one day to the next with no continuing trend (as would be the case with an actual leak) when there is no practical guarantee that the equipment is calibrated to that level of accuracy and that the natural variation within the system is greater than that level of accuracy anyway (making trying to measure and adjust to that level pointless).