Join Date: Sep 1999
Location: CT, USA
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TIre gauge accuracy (or lack thereof)
Last night I made up a tire gauge / airdown adapter, with a 30 psi industrial gauge, a valve, and a tire chuck. Went out into the driveway to try it out, ans surprise--- it doesn't agree with my "stick" tire gauge (a good quality professional one, not a cheapie) at all. Now I don't expect super accuracy at under 20 psi from a gauge that reads to 160, but I decided to check it, as the gague on the new setup was an old used leftover thing.
At work I borrowed a calibrated (0.25% accuracy gague) and hooked it up. Surprise, surprise! the "new" used gauge was OK and the stick gauge was off-- when the stick gauge read 22 psi I was actually at 16. I couldn't test much higher pressures as I didn't have fittings for the compressor, maybe the stick gauge is OK at higher pressures..... but not at the pressures I run! A real cheapie ($.25 in the closeout bin) was actually better than the expensive one, but still not good.
Anyway, the point is, don't believe gauge readings at the low end of the gauge's scale. If you want accurate readings under 20psi the gauge's max reading should be no more than 30 psi (careful, you could destroy it you run higher pressures on the street than the gauge's max reading!) If you use your own gauge all the time and know where it indicates (correctly or otherwise, as long as it's consistent) for the pressures you find work, fine, but don't expect the same readings with a borrowed gauge if you don't have your own with you.
Space isn't remote at all. It's only an hours drive away if your car could go straight upwards.