Is it normal? | FerrariChat

Is it normal?

Discussion in '348/355' started by Franc, Nov 5, 2009.

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  1. Franc

    Franc Rookie

    Oct 26, 2009
    27
    Manheim, PA
    Full Name:
    Francisco Lopez
    The four tires in my car appear to be losing pressure anywhere from 1 to 2 PSI per week, is this normal? the weather is getting cold but not too cold yet (it has been in the 40s).
    Thanks,
    Francisco
     
  2. Saint Bastage

    Saint Bastage F1 Rookie

    Jun 1, 2007
    2,548
    Connecticut
    Full Name:
    Lane
    Sounds right. I had to add a few pounds this last weekend. TPMS was singing like a Christmas village.
     
  3. rbellezza

    rbellezza F1 Rookie

    Jun 18, 2008
    2,793
    Henderson, NV
    Full Name:
    Roberto Bellezza
    I agree, during weather cooling the tire pressure goes down ...
     
  4. AceMaster

    AceMaster Three Time F1 World Champ

    Feb 6, 2009
    34,777
    Ontario, Canada
    Full Name:
    Mike
    That's odd, I didn't lose any pressure all winter and I live in a cold environment from Nov to March.
     
  5. Saint Bastage

    Saint Bastage F1 Rookie

    Jun 1, 2007
    2,548
    Connecticut
    Full Name:
    Lane
    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.
     
  6. ferrari 512 tr

    ferrari 512 tr F1 Rookie

    Nov 16, 2008
    4,180
    Australia
    Full Name:
    Paolo
    wow
    interesting
    u guys are the best
     
  7. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    9,727
    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.
     
  8. Saint Bastage

    Saint Bastage F1 Rookie

    Jun 1, 2007
    2,548
    Connecticut
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    Lane
    #8 Saint Bastage, Nov 7, 2009
    Last edited: Nov 7, 2009
    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.
     
  9. AceMaster

    AceMaster Three Time F1 World Champ

    Feb 6, 2009
    34,777
    Ontario, Canada
    Full Name:
    Mike
    Mitch, you are a human Encyclopedia :)
     

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