I did use a pencil gauge...and it was after driving the car. I guess i should check it when it is sitting for a while....and put it to about 35psi

 

You are probably right at 35-36 when cold....I've checked mine when cold and hot and found a 4 psi difference between them.

I usually run mine at 32 psi cold.

 

GM states that "cold" is when a vehicle has sat for 4 hours. Now I'm sure in colder climates that may vary. In my '07 Tahoe TPS light has come on when starting in the morning and showed 28lbs but after driving 8 miles it was at 32lbs.

 

My 17's read 35 cold and seen them go to 44psi on a trip to Fla running 75-80 in that heat in the south and back to 35 over night.

 

Should it be the same if you are running nitrogen in your tires? Does anybody know why you run nitrogen in your tires?

 

Yes it is the same. But if you are using helium make sure you have the required 50' rope for days when the barometric pressure is high so you don't float away.

Nitrogen molecules are larger than oxygen so the therory is that the normal loss of air is reduced, thus making tires safer because they hold their pressure better, which also leads to claims of higher fuel economy since the tires are always at or near the correct PSI. Proponents also claim that their will be less degradation of tire rubber since their is less moisture. I personally don't see the benefits outwaying the cost. But to each their own.

 

Thank you, the reason I ask is because the wheels/tires that I recently received are filled with it. No exp. with, so I wondered why.

 

 

I typically keep 78% nitrogen in my tires.

 

I have no idea what ratio is in there, does it matter?