You don't!

YOu buy another. I suggest a dial type over all others. The sticks are notoriously off and really so are digitals. Unless you are going to pay big money on a digital.

Here's the HD one I have... real nice, accurate and even has a tread depth gauge.

http://www.harley-davidson.com/gma/g...bmLocale=en_US

I can calibrate it for you based upon on a boost pressure sensor used in our trucks. Just have to T the sensor and gauge together and maintain constant pressure (I have a regulator). You can adjust the pressure gauge accordingly then so at 30 psi they both read the same. The boost pressure sensor has probably a few ops amps to lineraize the output, but it's probably within 1% of true gauge pressure. It would be more accurate than a 25 buck digital guage.

I'd have to subtract out the BARO as well.

What kind of place can do it?

Company that manufactured this one seems to be out of business. So much for the lifetime warranty.

Did you break your Google?

http://www.microqualitycalibration.com/overview.htm

JC

I was hoping for an answer like "take it to the firearms section of your local wal-mart and they can handle it" ;)

Yeah, just test it against a few others... if it's off the average by a pound or two, I'd take a sharpie and write the error on the dial face.

If it's off by more than a few pounds, I'd buy a new one.

I had one of those AutoZone gauges that I used for years... until I found out that it was 6 pounds off. I bought a nice liquid filled unit with a self correcting diaphragm from www.quickcar.net that I like a lot. They're about 40 bucks and pretty popular around the pits.

http://www.quickcar.net/tire_mgmt/lq_tire_ga.html

All you have to do, is reverse the polarity.

Or, you could just squint.

JC

You mean you can't tell the exact pressure just by looking at a tire?

tire places usually can do it for you, goodyear i know does it, seems like michelin and ev1 else should do it too.

i bought a craftsman digital one, havent looked back, very consistent, nice features. works for me.