How do you calibrate a tire pressure gauge?

[Sean]

Bought a fancy-shmancy tire pressure gauge, and the pressures we settled on at the track last weekend seemed way low. Today I tested it and 3 others I had laying around on a tire: 33.5 for the "good" one, 37.5, 38, 39 from the three others I had. Uh...

So how do you calibrate these things? I guess I just need to figure out how to get one accurate, then I can calibrate the rest off that one.

[Trip]

Unless it has a calibration dial, I wouldn't try to do it yourself, take it to a place that can do it.

If it is a new gauge, return it and say it is way off.

Or you can go the ghetto route and just measure a couple different pressures and figure how much it is off and just remember to remove that amount when using it.

[shmike]

Originally Posted by Sean

Bought a fancy-shmancy tire pressure gauge, and the pressures we settled on at the track last weekend seemed way low. Today I tested it and 3 others I had laying around on a tire: 33.5 for the "good" one, 37.5, 38, 39 from the three others I had. Uh...

So how do you calibrate these things? I guess I just need to figure out how to get one accurate, then I can calibrate the rest off that one.

Post up when you figure it out.

I had a similar issue recently but opposite from you.

The "good" analog gauge read about 3.5lbs higher than my cheapie digital that has served me well for years.

[Sean]

It's a Psiclops Extreme. I think the company went out of business. It has a dial on the back (at the bleeder button) which I assume is for calibration. The only way I know to calibrate these things is when tire companies set up tanks set at exactly X psi, and they only do it like, in the pits at Indy or F1 races.

http://www.northernautoparts.com/Pro...ProductId=2879

[askmrjesus]

The short answer is: You don't.

If you start out with a decent Accu-Gauge (aka a fancy-shmancy gauge) test it against another Accu-Gauge. If the reading is somewhere within 2% of the other one, you're good to go. Testing it against a pencil type gauge is useless, since they have a shit accuracy rating to begin with (5-10% being the norm).

At the end of the day, your gauge doesn't have to be "accurate", it just has to be consistent. Consistency however, is something pencil gauges lack, since dropping them on the ground once or twice, is enough to fuck them up.

ETA: I'm not familiar with the Psiclops, but the same principal would apply.

JC

[Sean]

Originally Posted by askmrjesus

At the end of the day, your gauge doesn't have to "accurate", it just has to be consistent.

Indeed. It is consistently inaccurate, so there's that. I really like this gauge (aside from the fact that it doesn't freaking work) because it's got some really cool features I haven't seen elsewhere. I think I'm just going to dial it up somewhere near what all the others I see read and call it a day.

[Homeslice]

Maybe take it to a dive shop. Good luck finding an appropriate adapter though, since dive tank fittings are totally different.

[askmrjesus]

Originally Posted by Homeslice

Maybe take it to a dive shop. Good luck finding an appropriate adapter though, since dive tank fittings are totally different.

Dive tanks are running 2250-3000 psi, so...good luck with that.

JC

[askmrjesus]

Originally Posted by Sean

Indeed. It is consistently inaccurate, so there's that. I really like this gauge (aside from the fact that it doesn't freaking work) because it's got some really cool features I haven't seen elsewhere. I think I'm just going to dial it up somewhere near what all the others I see read and call it a day.

That makes sense. All that really matters is that you get the same reading everytime the air pressure matches. If the gauge says 33.5, and you like how the tires feel, 33.5 is "correct".

JC

[shmike]

Originally Posted by askmrjesus

That makes sense. All that really matters is that you get the same reading everytime the air pressure matches. If the gauge says 33.5, and you like how the tires feel, 33.5 is "correct".

JC

True but it is tough to know your starting point.

If the Michelin rep says set your Power One's at 30/21 cold and your gauge is off by 10%, you could end up on your head before you get a chance to find the "correct" numbers on your gauge.