Tires always lose air in storage is this normal?

The super expensive Continental 5ps on the C63 lose air at about 10 lb ovr three months indoors.
There use to be some compound you can spread on the inside of tires to stop leakage. Western Auto sold tires that had a red liner in it for that purpose. they're gone of course.
Jut get a good gauge. I bought all the best gauges and not one of them works well. The expensive Pirelli brand dial indicator is off by as much as four pounds too low.

The basic thermo-dyamic equation is PV=RT (Pressure x volume = an atmospheric constant x pressure Since "R" is essentially the same every where on earth, it boils down to PV=T. In this equation, T is on the absolute scale.

Comparing temperature and pressure, the equation becomes P1*V1/T1 and is constant, disregarding leakage. If your tires are at a certain summer (or hot tire) temperature when you park it, the pressure will drop as winter sets in.

Just re-inflate to the recommended pressure before you start your spring travels, then keep tabs on it as the season warms up. Loss of pressure in storage isn't a harbinger of doom down the road.

Mine very consistently lose 5-7 lbs over the winter. It's also quite likely that you'll observe a greater loss if comparing them from hot weather to cold - that's not really a loss of air though - the cold air exerts less pressure.

10 -15 lbs over how long? What kind of rims do you have? It is not uncommon for cast aluminum rims to be porous and lose some air through the rim itself.

I just happened to air up for the coming winter adventures. I have 1 year old TransForce tires on the fifth wheel aired up to 80 psi.

Last fall I set then at 80 and hit the road. The camp0er set in the pole barn from March until today. No adjustments until today. They were all at 75 lbs.

You said: Tires always lose air in storage is this normal?

Let me rephrase: Tires always lose air is this normal?
(Note the deletion of "In storage")

The answer is yes. You may not notice it "In season" because you check more often and air up as needed (At least I hope you do) but, Yes, tires loose air pressure, always, Every tire, on every vehicle that has Pneumatic tires looses air pressure.

I once gave MY theory as to why a popular SUV got the nickname "Roll-a-matic" (More rollovers than any other ride out there or so it seemed.

This was part of the theory.

Some of it depends on what the outside temp was when you last checked them vs. what the the temp is now. They will expand or contract according to the temperature. My Michelins seldom if ever have required air if I check them when the temps are about the same. My cheap Chinese tires were always low.

B.O.

I'm always surprised when I check my GY Marathons on the 5'er. Even after 3-4 months over the winter, they're still within 2-3psi of 65psi.

It may depend on how long the trailer is in storage and at what pressure the tires
the tires are stored. Higher pressure may result in more loss over a period of time.

FWIW my toyhauler sat from November of last year to September of this year and the Sailun LT tires went from 100 psi to about 95 psi. Which is pretty comparable to what the change is in shorter periods. IMO 10-12 psi seems to be a bit too much. Probably not enough to be concerned with though.

If you're running ST tires the problem could be related to the thinner sidewalls of an ST tire. :)

pasusan wrote:
We have a TPMS and the vast majority of the time I just plug it in and the tires are all perfect. No lost air. This past summer we did have one tire that would lose about 6 pounds per month. We took it into the tire shop to have the tire resealed to the rim. Happy TPMS, happy me.

Same here. I lose a few lbs when the weather cools, just like you do in the truck tires, but never lose any just from sitting.

How old are the tires? Assuming you have rubber valve stems, if you bend the valve stem hard over do you see any cracks or hear any air hissing? Valve stems dry rot from UV exposure and can begin to leak or even fail. They should always be replaced when you replace your tires.