So the TPMS never seems to agree with the pump indicators. Which indication are you guys typically follow? I started looking for a high accuracy reader but the only one I came up with is a $300 model from tire rack.
Thoughts, feedback, etc?

 

Through the years, I've used several different kinds of tire pressure gauges, from the stick kind, to rotary gauges, digital readouts to gauges on my personal electric pumps. Not to mention gauges available at service stations, etc. (which I almost never trust). I've not found any two to read the same, even two gauges of the same type and manufacture. They all seem to measure within a couple PSI, though, which is good enough for me.

I use the TPMS on the car to set the pressure 1) to a desired point, and 2) to balance/equalize pressures among the four tires. It's good for that, and for learning on the fly how pressures change with temperature, speed, trip length, etc. That's all I expect.

Buying an expensive gauge to measure pressure to the tenth of PSI is probably appropriate in motor racing like they do with F1 tires. But for consumer use, it's about the same as buying $300 stereo headphones that produce sounds only dogs can hear... extreme overkill IMO, the expense is not worth it.

 

I use a stick type but all of them are not good. You need one that cost more than $5.

A digital gauge also normally is good but I hate they run out of battery and are dead when you need it.

But, the thing to know is that the TPMS sensors are not absolutely accurate either. You need to set your tires to your pressures using your stick or whatever you use knowing the readings are accurately set and then see what the car shows to you. I have one tire reading that is 1-2 psi lower than the actual pressure in the tire so for me it is normal for this one to show lower as I know what it means.

You set the pressures with your gauge and monitor tire wear across the width of the tire with a thread depth gauge that you need to have. This tells you the pressure you need to run with and then you can trust your TPMS values.

 

Pressure gauge has accuracy class.

I got this one : 0.5% accuracy, so they claimed.
http://www.longacreracing.com/produc...Gauge-0-60-psi
It is good for its price.

And for the analog one, I use Wika gauge while the hose I use some low cost one and remove its pressure gauge and use the Wika. This is a low 2.5% accuracy reference.
The key to analog bourdon tube gauge of choice is, try to get the reading you want to be at the 12 o'clock position or 50% of the scale for best accuracy from the mechanical side of the gauge.
So 0-60 psi is good to use, but a 0-100 psi one would do for me as I sometime use the 42 psi reading for high load and high speed.

I use the analog Wika, this one : https://www.augustindustries.com/pro...e-100-psi-bar/

Here is some of the calculation I did : See the MIDDLE SCALE 1/2 or at 50% of scale, its accuracy is better than Lower 1/4 and upper 1/4 of the scale. This is how a bourdon tube gauge works.









Even though I am a metric guy, if tire pressure speak I am a PSI guy. Its the habit since my 1st car in the 80s and my diving habits too which all were PSI gauges back then in early 90s.

If you really want higher accuracy, use this gauge, but it is a G 1/4 and not NPT 1/4 and it is BAR, but 3 digits after decimal.

0.1% accuracy https://www.kelleramerica.com/digita...ure-gauge.html
0.2% accuracy https://www.kelleramerica.com/digita...ure-gauge.html
0.5% accuracy https://www.kelleramerica.com/digita...ure-gauge.html

I use the 0.1% Keller gauge for my dive compressor final output at 3,000 PSI or 204 BAR.
I use the 0.2% Keller gauge to monitor my interstage pressures on my 3 stage dive compressor, stage 1 and stage 2 pressures which are only <10BAR and <70BAR respectively.

The Wika analog bourdon tube gauge is really good, it is robust and it last very long even at high pressure shock cycle.
I suggest use liquid fill Wika if analog, because liquid fill gauge can handle rough use. Bourdon tube gauge is actually a sensitive item and not to be dropped.
The liquid fill absorb those shocks.

Avoid a tire pressure gauge with too long a hose.
The longer the hose, the more you loose air when measuring the pressure and you may take it as inaccuracy of say 0.1 or 0.2 psi, depending on how big ur tire is.

I also bought 4 cheapo china made tire digital gauges for fun sake. I then select them for their accuracy.
The one with 0.5psi accuracy at 32 psi, I keep them on my cars as back up while on the road.

The Logacre gauge I keep at home.
I do not fill up my tire with normal 12V baby compressor air, I use my dive tanks which is 0.05% humidity and it is by default 78% nitrogen, which our atmosphere is.
If I do tire change, they fill it up with supposedly 100% nitrogen.

The drier the air inside your tire, the better it is for rust protection from condensation.
In fact I usually fill-empty-fill (flushed) up to 4 times the air in my tire whenever a new tire get installed or has been punctured repair.
I jacked the car up, so tire does not get deflated by car weight.

As to why I do not really trust tire shop nitrogen air, it is not the % of nitrogen I do not trust, it is their air dryness ( dewpoint ) I do not trust to be as dry as my dive compressor.
So I may loose extra 22% nitrogen, but I am guaranteed a very dry air if I use my own dive tanks air.

Yes, I am super **** on air quality & dryness for breathing purpose underwater.


In my younger reckless days, a different house and country back then, I have this corner near my house which I can do decent g-force /speed during the cornering.
I pass the road everyday and many times a day for years and years, I can actually detect if my tire loose 2 psi, due to the change in traction.
Hence I really think pressure gauge accuracy is a must for our tires, if you really like to corner fast or do Autobahn kind of high speed or want your tire wear as even as possible,
or simply you like high accuracy parameters.

Happy shopping.....

 

WOW.... great post on pressure gages...

 

Is there a way to see the tire pressure being read by the TPMS system per wheel?

 

On my 2016, you can, so I suspect your one year earlier model can as well.

Use the left arrow on the steering wheel until you see a screen with tire pressure, then down arrow and OK. Pressure in each wheel is shown. These are equal, but where pressure differs per wheel, you will see it.

Page 294 in the manual... The manual reveals all. RTFM...

 

I build my own tire filling chuck with industrial gauge in 6" diameter for reading accuracy.
When all gauges have their tolerances, I always compare new gauge to 1 I know is pretty accurate and than try to remember the tolerance.
The "pencil" gauges is 1 of ****test gauges, but pretty convenient to carry in the car for emergencies.
When you reset car TPMS, make sure you do it on cold morning as during the day the pressure increase and if you set it after some driving, you will have alarm next morning.
45 psi in front tires. I bet that makes your dentist happy

 

I think it is only in the U.S. where the government requires to have individual tire pressure readings. Canada and Europe use wheel speed data to detect low pressure in a tire so when cold weather comes all tires go low and the system thinks all is good. Unless these other countries changed recently...

 

My ( cheapo) rmarket only get TIRE PRESSURE LOSS warning...
Which I believe the system calculate wheel RPM vs speedometer and a deflated tyre will have less OD... something like that.
Its too stingy this local assembled model to not have proper TPMS.
I did try to use aftermarket one ( with valve cap sensor ) but one sensor died in a few months and also its display is not bright enough during daylight.

 

the US 2008 models had that as well, but taking a scanner I could read the actuall psi values and temperature on top of it.

 

That means there is an actual pressure sensor inside each wheel ? Mine is NIL . I know US laws about must-have TPMS...which is good.

 

Nothing in this life is definitely good or definitely bad.
When newer MB TPMS allow for reading the pressure, what is convenience - they have about a minute or 2 delay. So when your car loose the air overnight, it will take driving some distance on flat tire before the warning will show (that actually happen to me),
Don't know how rpm comparison would act, but I assume it would act right away?
My Ford truck displays pressure right after the start. Still not sure if that is live values or something it remembers from the past.
Than non-US MB models do have pyrotechnic hoods, Is it better?

 

Nope, the RPM comparison is not immediate and it won't register fast if you drive aggressive, so I read in the User Manual.
I also do not know how at many psi reduced from the reset value, will the alarm be triggered.

I would prefer pressure sensor anyday but the one inside the wheel and not valve cap one.
But too bad my dashboard is not designed to accept the wireless transmission of those sensors.

If I leave the house and only know of lowered tire pressure of X value in 2 minutes, I won't mind.
What I find most important is during long drive at higher speed and if my tire get punctured by something with leaking speed of say 5 psi an hour,
that is where the pressure sensor will shine. I fear high speed blow-out or unknown tire pressure loss exceeding 10 psi.

At 10 psi lowered tire pressure, when I corner agressive, car will loose traction a great deal. I had once it happened to me on a Suzuki Vitara.
It was rear left wheel and I was taking a fast left and right corner ( kinda S bend ). When it was left corner its okey, when I swing to the right corner, then sudden oversteer kicked in like on oil spilled road... with very loose rear end.
It was 22 psi vs my normal 32 psi. So a 10 psi lost and its no fun. It was a nail.

Anyway in my city there used to be azzholes criminals who will throw tire spikes on the road, like below photo :


So when you stop to check the tire, they either robbed you or steal your stuff inside the car.
Today is much less for this kind of crime in the city but it can happen when doing inter-state be it on B road or highway, but I am "trained" to be always cautious and told my driver to drive slow but non stop
when wheel get punctured , to nearest safe spot and ram/run-over any azzhole ( usually on a motorbike ) blocking his way if he needs to. Damage the tire if he has to or the bumper, no problem, my kids and wife safety is no 1.

.

 

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