Tpms accuracy

How accurate are the tpms sensors? Im setting mt tires to the 32psi required measured w a pretty good gage. Im off by 3 lbs

 

My dash matches my gauge exactly . I set mine on 33 the other week and dash had all 4 on 33 .
You say you are off by 3 pounds it's the gauge that's off .

 

Same here, mine match the gauge spot on when checked cold.

 

How did you determine you have a 'pretty good gauge'?

Cross check with a calibrated gauge?

Or it's a pricey gauge, like Intercomp?

 

Don't have a gauge just a light but I'm not impressed with the accuracy. Have my winter tires/rims on with no sensors and in about 14 miles it informs me that all 4 tires are flat.

 

You are giving it nothing to be accurate with.

 

Some of these threads/posts these days are so mind numbing that all I can do is burst out in laughter and move on.
“Not impressed with accuracy”. No sensors. LMFAO.

 

Poor practice to check the "accuracy" of a gauge against a gauge with unknown accuracy.

You don't know which one is correct or closer to correct......

Best you can hope for is to have matching readings.

 

my gauge indicates 32lbs and my tpms readings hover from 36-40lbs. somebody's not telling me the truth

 

I'd suspect neither gauge is correct.

Use which ever gauge you want to inflate the tires, set the TPMS system at that point. Then ignore the readings from the other gauge.

 

I had a dial gauge on my air line to show the regulated pressure. I discovered recently that it was off by 10 psi! Now I know why my air tools didn't seem to have the power that they used to have.

 

Well do you think it might just be able to detect there is zero pressure/reading? So what makes it decide after 14 miles or so that there is no reading or no pressure? These things have batteries so they in and of
themselves they are the transmitters to the in dash system. Mine does not report the location only that somewhere there is a low tire. I just kind of think it should report in a little more timely manner. Now to it's benefit if it is driven more often it does often throw a code quicker or on startup. I don't really care because this is the only vehicle I have ever had with sensors so my tire pressure gauge lives in the glove box and is used often by habit.

 

These mass produced cheap gauges have "accuracy" numbers all over the place.

Don't expect more than about 5-10% full scale accuracy. In other words, a gauge with 50 psi max will have an accuracy +/- 2.5-5 psi. So, the gauge won't know the difference between 45 psi or 55 psi.

To cook it down for a little more clarity.
Assume you have a gauge with a 50 psi full scale reading with a +/- 5% accuracy. The error range is +/- 2.5 psi. So, at a tire pressure reading of 32 psi means the actual pressure in the tire is 29.5-34.5 psi.

There are other parameters to measure gauge accuracy........such as Repeatability, hysteresis, non-linearity. But those discussions are moot for tire pressure gauges, but relevant for lab grade gauges.

 

Accurate enough to be of no concern. In other words, if you run on the recommended pressure stated on the door label, you maybe looking at .5psi accuracy deviation.

If you run 100psi, its like 3psi, not something to get OCD over as psi will fluctuate along with air temperature anyway.

Moreover, the typical tire gauge stem outside the tire, maybe pushing into different atmospheric conditions than the sensor that is inside the tire.

Hope that helps

 

15 miles is the default used when the TPMS is reset.

While you may not have hit the reset button, the system is 'looking' for a reading. Any reading.

You aren't giving it any, so the light comes on.

If sensors are changed and the reset process doesn't work (say it's done improperly) the same thing will happen.

 

Just pick up a gauge by a reputable company. That may mean it's a little more expensive, but it's one of those things that can be worth the extra dollars depending on the features.

FWIW, I use a Viair pressure gauge and it works extremely well (ha what else would it do?) and it is spot on w/ the TPMS on my truck.

$29 Viair 00032 Air Down Gauge

https://www.amazon.com/VIAIR-00032-...ure+gauge&qid=1611761292&s=automotive&sr=1-10

 

My TPMS is spot on and most cars I work on are really accurate too. I use a liquid filled Longacre gauge and it’s accurate to .5 PSI. I’ve checked it against other gauges and I fill enough cars at work to know that it’s accurate. Unless you own anything that requires really high PSI then the best is to get a gauge that’s 0-60 PSI or so. You get better resolution or accuracy on the readings vs a gauge that reads over 80 that most people will never use. Also, I’m just not a fan of digital gauges. Lastly after I fill or remove air from the tire, I always pop the chuck off and on the valve stem to check the PSI 2-3 times and make sure it’s a consistent reading. I guess I’m just OCD.

 

My analog gauge agrees with two others that I have. The dash numbers are about 7 or 8 pounds lower. Which am I to believe? BTW the tires wear evenly.

 

A wise man said a man with one watch always knows the time. A man with two watches is unsure.

Pick one gauge and trust it.

 

According to my digital tire gauge, vs the one on the trucks dash, the dash gauge reads 1lb. high.