How can you possibly trust your tire gauge?

Elkins45

Elkins45

Joined
May 7, 2018
Messages
1,744
Location
Northern KY
The low pressure light came on in my car this morning so I grabbed the tire gauge in the glovebox and checked one. Imagine my surprise when it rocketed up to almost 50 psi. The tire was no more than 35 psi even before the light came on, so that gauge is worthless. That’s the worst example, but every tire gauge I have reads different. I finally decided to standardize on a US made one I bought from Amazon, but I still have no idea if it’s accurate.

How does someone find out what the true pressure reading is on a tire, or to calibrate a gauge?
 
Is your gauge mechanical or digital? I've had consistent readings with Accutire brand gauges and the results are identical to one another (comparisons with the same model). I don't think consumer grade versions are designed for calibration by the user since this is not practical.
 
That's a good question. It might be worthwhile to find out what gauges racing teams and tire testing organizations use. Maybe @CapriRacer can jump in here.

Is it more important for a gauge to be precise or consistent (within a certain margin of error)?
 
Elkins45 said:
The low pressure light came on in my car this morning so I grabbed the tire gauge in the glovebox and checked one. Imagine my surprise when it rocketed up to almost 50 psi. The tire was no more than 35 psi even before the light came on, so that gauge is worthless. That’s the worst example, but every tire gauge I have reads different. I finally decided to standardize on a US made one I bought from Amazon, but I still have no idea if it’s accurate.

How does someone find out what the true pressure reading is on a tire, or to calibrate a gauge?
Click to expand...
I have seen so much variablility in pencil gauges. I have a husky electronic which seems accurate, but if leave the batteries in, they are dead in a month.

I bought these calibrated pencil guages on amazon and they mimic the TMPS numbers in my truck , so far they work well and are inexpensive.
The set comes with 2. One for 50 psi and another that goes to 120. I keep my truck tires @65-70psi and my travel trailer tires @65psi.


Unfortunately the COO is China. If someone has better gauges that are non-China, please post links!

1701024809214.jpeg
 
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I ordered a Milton pencil gauge for just this reason and it was junk. I don't remember the exact problem but recall being severely disappointed and feeling it was either very inaccurate or inconsistent. I threw it away.

And yeah I personally won't bother with digital because I'm unwilling to be a slave to button (or letter) batteries.

I've basically concluded the best course of action is to buy inexpensive pencil gauges and check them against [something else]. If they seem to operate within the realm of believability that's good enough for what I need (shrug). I also typically check at least twice. Three times if I need a tie breaker.

My wife is terrified of anything pressurized and prefers to thread on the M12 inflator to get a reading (there's a mod to go to a quick connect fitting, too). I think it's dumb but at least she's checking so I won't complain.
 
LongTime_Lurker said:
Is your gauge mechanical or digital? I've had consistent readings with Accutire brand gauges and the results are identical to one another (comparisons with the same model). I don't think consumer grade versions are designed for calibration by the user since this is not practical.
Click to expand...
I have 3 and they all agree plus they agree with a couple digital units and within a psi or two of two in pump gauges. Surely the odds of all 7 in reasonable agreement being wrong are fairly low
 
I have a portable compressor with a (dial) gauge on it, and I also have a cheap pencil gauge from Walmart. Their readings are close enough, unless the pressure is really low and the pencil gauge doesn't move at all :cautious:
 
slacktide_bitog said:
I have a portable compressor with a (dial) gauge on it, and I also have a cheap pencil gauge from Walmart. Their readings are close enough, unless the pressure is really low and the pencil gauge doesn't move at all :cautious:
Click to expand...
Yep, I've also purchased low pressure pencil gauges for the SxS's I service and I keep one for airing down the Jeep. When you want 12 or 13psi a 0-50 gauge just doesn't have the resolution
 
We use these at work. Different sizes for different applications. We ship them out once a year for calibration. Good to .1% of reading.


 
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I never use pencil or other glove compartment gauges. I trust them enough to know that there's "enough" air in the tire to get me to a place where I can have the pressure checked by more fisticated means. I routinely check/adjust the tire pressures with the gauge on my Milton inflator.

I have three gauges that I can find; two pencil gauges and a fat, old Schrader "Balloon Tire" gauge that no longer seals on stems. All three are made in the USA.

I distinctly recall having a pencil gauge that was adjustable for calibration. You pull out the gauge, insert a paper clip or similar into a hole in the side of the body and rotate the gauge CW or CCW to calibrate. I never did this for lack of a standard. I think this gauge might be in the Camaro someplace. 🤷‍♂️
 
JeffKeryk said:
I use a Milton pencil gauge. But mostly just set the Milwaukee inflater and let 'er rip.
Click to expand...
The TPMS on the Maverick is within one psi of the $8 Milton pencil gauge that I've had for 10+ years. It is even accurate compared to BMW's Motorrad TPMS system. Very good system BTW. Also the Milton is within 1 psi of my 32 yo BMW motorrad pencil tire gauge, which is from when my 1991 R100gs was new.

Here is the one I have S-921. Has only gone up $2
 
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