tire pressure

A year or so ago I bought a plug-in tire inflator for our car. Our 6 year old Subaru came with self minding tire pressure indicators and the silly things started telling me I had low air pressure. I got tired of visiting pay as you go air pressure pumps and broke down to make a more convenient purchase.

I used the machine once and it seemed to do the job just fine. Start the car, prepare for the ungodly loud racket of a very small pump trying to put out sufficient volume of air to re-air automobile tires and then sit there for what seems an eternity until the little pump does its job. All in all, other than the noise, it worked just fine.

Summer turned to autumn, autumn into winter and winter into spring. Boing, there goes the low-air pressure warning again. So I get out the inflator and try to remember how to use it. I get out the manual (still in the box, on the floor behind the driver’s seat) read what I think are the pertinent parts and get started once again.

ours looks a lot like this

The machine has a small illuminated screen and the screen sort of lights up — in daylight you can barely see the numerals. But…. the numbers don’t match with air pressure any more. Hmmm. I putz around without looking at the manual. Plug it in again and start pumping with what I believe to be the right setting and it goes and goes and goes and goes. — All to be expected when a teeny tiny pump has to air up a big tire.

Long story short, I finally realized (by reading the directions) that the cute little machine actually has four different scales: Atmospheric pressure is expressed in several different systems of units: millimeters (or inches) of mercury, pounds per square inch (psi), dynes per square centimeter, millibars (mb), standard atmospheres, or kilopascals. Turns out I had set the pump to a setting way higher than I wanted — no wonder it was taking so long!

Error corrected, I reset the scale and the little pump did its job nicely.

The moral of the story is don’t just read the instructions ONCE. Never be afraid to re-read them — which pre-supposes you haven’t thrown them away with the packaging. Little life lessons for the aging. 🙂 I can’t believe it took me until 74 to buy one. I used to have a decent pump and reservoir. Hell, I used to go to gas stations where they had FREE air pumps AND pumped your gas for you for free. Oh well, the world changes and we have to embrace change. Right?