I recently got a bourdon tire gauge and realized it lists the units as psi, when it clearly should be psig (the meter starts at 0). This got me thinking, on tires, it also lists psi... Ive never heard of adding 15 after doing a measurement. At the same time I've never seen psig on tires or gauges.

So which is it?

12/28/2010 12:20:37 PM

12/28/2010 12:34:15 PM

if this thread is serious, then -

you are reading a gauge when you measure tire pressure.

12/28/2010 1:17:52 PM

You'd have to be dumb to want it to read PSIA. You have a gauge, it is giving you Gauge pressure.

You don't want PSI-A on tires because then you'd have to correct it for atmospheric conditions which would suck.

12/28/2010 1:23:05 PM

sumfoo1upper

12/28/2010 1:24:40 PM

Sorry Dr.p Big fan of your drink buddy, honestly i didn't read the post i just started :rant:

You should have seen what i said when someone posted they were running 12PSIa on their waste gate.
I was unaware you could set a waste-gate to vacuum.

12/28/2010 1:32:26 PM

well, yeah. i was referring to the atmospheric corrections part

12/28/2010 1:55:00 PM

Dr. Boles approves this thread

12/28/2010 6:35:55 PM

Got it.

Psi = psia in textbooks
Psi = psig on tires

12/28/2010 8:11:30 PM

ahahha sweet jesus


I think, the old tdub garage might have just jumped the shark.

12/28/2010 8:26:54 PM

PSIa= ABSOLUTE PRESSURE

PSIg= Absolute pressure-atmospheric pressure

12/28/2010 9:24:24 PM

there are a lot of tire gauges that read in absolute and not gauge and this can cause headaches and potential deadly accidents if a tire blows up. the best solution is to puncture one tire (only one though) and after it has deflated check what your bourdon tire gauge reads. If it reads 0psi then you have psi-g and if it has the atmospheric pressure then you now know for sure and you also have a great way to predict incoming storms.

12/28/2010 11:37:23 PM

^^ I was asking what the convention of plain "psi" labeling on tires was. I know the textbook definition of psia/psig; I thought it was confusing since I've always seen psi implying psia.

12/29/2010 2:04:19 AM

Quote :

"there are a lot of tire gauges that read in absolute and not gauge and this can cause headaches and potential deadly accidents if a tire blows up. the best solution is to puncture one tire (only one though) and after it has deflated check what your bourdon tire gauge reads. If it reads 0psi then you have psi-g and if it has the atmospheric pressure then you now know for sure and you also have a great way to predict incoming storms. "

was about to flip shit until i actually read this statement - sound advice.

12/29/2010 8:24:24 AM

^ yeah i said wtf... wait... lols

12/29/2010 8:53:06 AM

http://www.dailymail.co.uk/news/article-1342224/Boy-8-killed-tyre-changing-father-explodes-sends-flying-garage.html

12/30/2010 4:35:25 AM

Ohh no, he thought it was absolute :-(

12/30/2010 9:31:52 AM