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[Midgad]

...so about a month ago had the first onset of cold weather here in the Northeast...
I start my 1 and get the low tire pressure warning.
...so learn we lose a few pounds of tire pressure when the temp goes down and the sensors freak out.
Question;
Today had the pressure sensors go off again! (18 degrees). Wow! The pressure was down like 4-5 lbs.
No prob, stopped at gas station and filled RF's back to 33 lbs.
Cool! warning light went out without having to reset, but wanna know...
Will I keep losing pressure when the temp gets lower and lower and have to keep adding air?
Most importantly, what happens when we hit 60 degrees again? Will I have like 45 psi and have to let air out and reset sensors?
Is tire pressure maintainance an ongoing issue in the winter(with RF's)?
Should I keep refilling as the temp goes down, and reduce when temp goes up??
:iono:

[lambammm]

yes, or just use nitrogen like the rest of us, you didn't get the memo?

your tires don't typically just blow back up, i never have to reduce air pressure.

[Guildenstern]

How would Nitrogen not loose pressure with a 42 degree drop in teperature? It still must follow the ideal gas law: PV=nRT

If we do some Mathemagic we end up with:
P1/T1=P2/T2
Pressure Divided by Temperature. Before and after.

so 33/289=P2/265 <==Gotta put temp in Kelvin
Cross Multiply
8745=289(P2)
P2=8745/289=30.2 PSI

You still loose pressure even with an ideal gas (which Nitrogen isn't) which has no moisture (Nitrogen is dry).

Yes you loose a bit less pressure than humid air, but in genneral it's not worth any extra hassle.

And Midgad:
Yes you need to check and adjust your tire pressure at least monthly like the manufacturers reccomend. Just do it every time you wash the car, or fill up or whatever routine works for you. Or just listen to the TPMS. (Those became mandatory because people wern't checking their tires.) But Labammm is right, I've never really ended up with overpressured tires after winter. But remeber it's easyer for a higher pressure to leak out. So it may just seep out gradualy as the temperature goes back up in spring.

[Midgad]

Originally Posted by Guildenstern

How would Nitrogen not loose pressure with a 42 degree drop in teperature? It still must follow the ideal gas law: PV=nRT

If we do some Mathemagic we end up with:
P1/T1=P2/T2
Pressure Divided by Temperature. Before and after.

so 33/289=P2/265 <==Gotta put temp in Kelvin
Cross Multiply
8745=289(P2)
P2=8745/289=30.2 PSI

You still loose pressure even with an ideal gas (which Nitrogen isn't) which has no moisture (Nitrogen is dry).

Yes you loose a bit less pressure than humid air, but in genneral it's not worth any extra hassle.

And Midgad:
Yes you need to check and adjust your tire pressure at least monthly like the manufacturers reccomend. Just do it every time you wash the car, or fill up or whatever routine works for you. Or just listen to the TPMS. (Those became mandatory because people wern't checking their tires.) But Labammm is right, I've never really ended up with overpressured tires after winter. But remeber it's easyer for a higher pressure to leak out. So it may just seep out gradualy as the temperature goes back up in spring.

Hey Guild,
Thanks for the great reply!
Sorta sucks because we have such variations in temp that wonder if the tpms are going to keep going off with each temp fall. Guess its the price ya gotta pay for having the RF's.

[Guildenstern]

Well its more the price you pay for the Bridgstone/firestone/ford explorer fiasco. Even non Runflat Cars require them for either 08 or 09 model year I think.

Just check em once a month runflat or not, and if you get an alert just hit the nearest gas station and blow em back up. (Unless they charge for it, jerks)

[lambammm]

Originally Posted by Guildenstern

How would Nitrogen not loose pressure with a 42 degree drop in teperature? It still must follow the ideal gas law: PV=nRT

If we do some Mathemagic we end up with:
P1/T1=P2/T2
Pressure Divided by Temperature. Before and after.

so 33/289=P2/265 <==Gotta put temp in Kelvin
Cross Multiply
8745=289(P2)
P2=8745/289=30.2 PSI

You still loose pressure even with an ideal gas (which Nitrogen isn't) which has no moisture (Nitrogen is dry).

Yes you loose a bit less pressure than humid air, but in genneral it's not worth any extra hassle.

And Midgad:
Yes you need to check and adjust your tire pressure at least monthly like the manufacturers reccomend. Just do it every time you wash the car, or fill up or whatever routine works for you. Or just listen to the TPMS. (Those became mandatory because people wern't checking their tires.) But Labammm is right, I've never really ended up with overpressured tires after winter. But remeber it's easyer for a higher pressure to leak out. So it may just seep out gradualy as the temperature goes back up in spring.

wow you got all equationy on me there. i don't really use nitrogen, just heard it works. so excusssssse me mr. scientist. :biggrin:

[Red Bread]

Originally Posted by lambammm

wow you got all equationy on me there. i don't really use nitrogen, just heard it works. so excusssssse me mr. scientist. :biggrin:

Nitrogen is the greatest scam, and a financial windfall for all the car shops since we worked out that colored wax really doesn't work. I wonder how many shops sell "nitrogen", yet really just pump out regular air?