View Full Version : How do you calibrate a tire pressure gauge?
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.
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
08-16-2010, 06:21 PM
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. :idk:
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/ProductDetail.cfm?ProductId=2879
askmrjesus
08-16-2010, 06:45 PM
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
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
08-16-2010, 06:54 PM
Maybe take it to a dive shop. Good luck finding an appropriate adapter though, since dive tank fittings are totally different.
askmrjesus
08-16-2010, 06:57 PM
Maybe take it to a dive shop. Good luck finding an appropriate adapter though, since dive tank fittings are totally different.
:lol:
Dive tanks are running 2250-3000 psi, so...good luck with that.
JC
askmrjesus
08-16-2010, 07:00 PM
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
08-16-2010, 10:00 PM
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.
Gas Man
08-16-2010, 10:38 PM
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/gma_product.jsp?PRODUCT%3C%3Eprd_id=84552444229241 5&FOLDER%3C%3Efolder_id=2534374302290427&ASSORTMENT%3C%3East_id=2534374302290427&bmUID=1282012661172&bmLocale=en_US
101lifts2
08-16-2010, 10:40 PM
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.
Unless it has a calibration dial, I wouldn't try to do it yourself, take it to a place that can do it.
What kind of place can do it?
Company that manufactured this one seems to be out of business. So much for the lifetime warranty.
askmrjesus
08-18-2010, 01:50 PM
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" ;)
OreoGaborio
08-23-2010, 01:14 PM
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
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.
All you have to do, is reverse the polarity.
askmrjesus
08-23-2010, 06:43 PM
All you have to do, is reverse the polarity.
Or, you could just squint.
JC
Cutty72
08-23-2010, 10:49 PM
You mean you can't tell the exact pressure just by looking at a tire?
Dnyce
08-24-2010, 01:21 AM
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.
I was hoping for an answer like "take it to the firearms section of your local wal-mart and they can handle it" ;)
Ahh yes, the rider method :lol:
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