Is it normal?

Sounds right. I had to add a few pounds this last weekend. TPMS was singing like a Christmas village.

 

I agree, during weather cooling the tire pressure goes down ...

 

That's odd, I didn't lose any pressure all winter and I live in a cold environment from Nov to March.

 

Its not a loss of air but a change in density caused by temp. It becomes very obvious when you see pressures and temps on a TPMS. My pressure increases about 4 psi based on tires warming up. I'm told its one of the reasons people use Nitrogen (N) in the tires. Temp differances do not affect N density as much improving pressure consistency across a wider thermal range. Blah, blah, blah, yeah so what, easier to connect a compressor.

 

wow
interesting
u guys are the best

 

Close:

Air changes pressure with temperature (that PV=NRT thinigie).
As the air temperature gets closer to 212dF the water vapor increase its partial pressure inside the tire from just a little pressure down near 140dF to significant pressure up at 212dF and above.
Nitrogen is dry--that is why people who use tires with large swings in temperature like it. (Racers and truckers)
Any vapor that is dry is essentially equivalent in this respect.
Air also has oxygen. If this is left inside the tire for long periods of time it will decay the rubber. This is only an issure wih truck tires.

 

I agree Mitch...just didn't want to get that technical. Thanks for having the patience.

For those that care, "Air" in our atmosphere is made up of about 20% Oxygen, 75% Nitrogen, and <5% other stuff. As Mitch states, Oxygen is an oxidizer where Nitrogen is inert.

 

Mitch, you are a human Encyclopedia