Tire Pressure Gauge Accuracy

[JohnVee]

How do I know which of the handful of gauges I have is the accurate one? Each one is different over a 10psi range. I even rounded up 3 different compressors and filled 3 tires to 40psi by their gauges. I got different readings with each gauge on each experiment and was able to determine that the compressor gauges are also off from each other.

My theory is that this is one reason why people have such huge variances in pressures.

Is there a best brand/model or a calibration standard?

--john

 

[skidplate]

I just use the scale on the tire chuck, buy a good one, it is accurate with the little pencil, pocket one I have.

 

[cruiserpilot]

I have noticed the same thing. I settled on a tire gauge from blue point, it has a 12" hose whip and it compares to 2 pencil gauges I have. The blue point has a round dial gauge, and I like it's easy to read dial. I went to a tire shop, and they used 2 different electrical digital gauges, neither was accurate to within 5 psi. I have found that pencil gauges are the most consistently accurate gauges that you can buy off the shelf for least amount of money.

 

[gaijin]

How do I know which of the handful of gauges I have is the accurate one? Each one is different over a 10psi range. I even rounded up 3 different compressors and filled 3 tires to 40psi by their gauges. I got different readings with each gauge on each experiment and was able to determine that the compressor gauges are also off from each other.

My theory is that this is one reason why people have such huge variances in pressures.

Is there a best brand/model or a calibration standard?

--john

There's no way around it - if you want to know what your tire pressure really is, you need a quality gauge.

I bought one of these a few years ago and stopped worrying about whether my pressures were accurate:

http://www.intercomp-racing.com/Products/9999_PSI_DIGITAL_AIR_PRESSURE_GAUGE_704.cfm

It's not cheap, but you will know for sure what pressure you're running.

 

[Pin_Head]

Is there a best brand/model or a calibration standard?

--john

The gold standard is when the gauge calibration is traceable to NIST, the national institute of standards and technology. We use stuff that is calibrated according to NIST all the time at work.


I don't think that you need that level of accuracy though and a major limitation for tire gauges is the precision with which you can read them and their reproducibility. Most of the ones that I encounter are reproducible to +/- 1 PSI. If they are not reproducible, I throw them away.

 

[JCruse]

Several years ago I bought a Psiclops XPRS gauge with single hose and bleeder valve when tirerack had them on sale and it's what I use when I want accuracy. It's supposed to be accurate to 2% I believe, has a quick connect, air inlet, bleeder button and the gauge is back-lit in red and blue as soon as air goes in. It's cast aluminum with a thick braided hose, a sturdy carrying case, and I've been very happy with it. All my other gauges read somewhere around it but this is the one I count on for accuracy.
I also use it for airing up, both for it's quick connector and since the TJM compressor gauge is not as accurate.

Most analog pressure gauges have a "sweet spot"; a pressure range where it is most accurate. PsiClops gauges have a unique gauge mechanism that allows for 2% (+/-) accuracy throughout the range of the gauge eliminating the "sweet spot".

 

[JohnVee]

Thanks for the info, everyone. Keep it coming. I think I'm probably just going to buy a variety of gauges and test them against a known standard somewhere then return the ones that don't cut it (I'm gonna hate returning the cheap $2 ones but I anticipate buying a lot of them!). I will most definitely make sure to include some low pressure-specific models.

--john