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Cold temp droped tire pressure 7lbs

Discussion in 'Gen 2 Prius Fuel Economy' started by nickfromny, Oct 10, 2008.

  1. nickfromny

    nickfromny Member since 2007

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    Presure back up to 42f/40r and mph is back up over 50mpg. Winter is comming.
     
  2. Sheepdog

    Sheepdog C'Mere Sheepie!

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    yet another reason to think about Nitrogen. My Tire pressure is exactly what it was when filled. 42/40. 10K miles now not a single pound difference than when set.
     
  3. Neicy

    Neicy Member

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    :Cry::Cry::Cry:
     
  4. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    TP is something you should check on a weekly basis no matter what the season
     
  5. jdenenberg

    jdenenberg EE Professor

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    Ignoring the possibility of a leak, PSI is guaranteed to drop as air temperature drops.

    Warning Tech Alert
    - The relevant formula is P*V=N*R*T where T is absolute temperature (P is Pressure, V is Volume, N*R is the amount of air in the tire). So a 50 degree drop in temperature results in approximately a 10% (4 PSI) drop with dry air (or nitrogen - no difference). Moisture in your tires can cause a slightly higher drop in PSI. (sorry, I'm an engineering professor and can't help myself)

    JeffD
     
  6. richard schumacher

    richard schumacher shortbus driver

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    That means (1) whoever mounted the tires did a good job, and (2) the tire temperatures were the same at the two measurements. The nitrogen fill had nothing to do with it other than being a relatively dry and inert gas; air, argon, or sulfur hexafluoride would have worked just as well :_>
     
  7. Codyroo

    Codyroo Senior Member

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    Man! Don't let the cat out of the bag with that one! If everyone finds out about it.....then they'll all want it......

    Nothing to see here....keep moving....
     
  8. richard schumacher

    richard schumacher shortbus driver

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    They can clamor all they want, but it's an extremely efficient greenhouse gas so it will never be legal for tires.
     
  9. N3FOL

    N3FOL Member

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    This time of the year, I check my tire pressure every 1.5 weeks not longer than 2 weeks. Only a couple of my tires are dead on the spot where I want it to be...and I add just a little air on the rest. Keep it this way and your tires will last longer too. I am a little over 14K now and tires still look great.
     
  10. qbee42

    qbee42 My other car is a boat

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    +1. Living in a warm climate does have some advantages, other than big bugs.

    Tom
     
  11. 13Plug

    13Plug Active Member

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    My TPMS light came on last week. The cold weather and the fact that I haven't checked my tire pressure since August both played a role. I pumped them back up to 38/36 and all is good. I'm putting on winter tires in the next few weeks anyway. I'm gonna have to live with that pesky light all winter long.
     
  12. nickfromny

    nickfromny Member since 2007

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    Black Duct tape will hide it just fine.
     
  13. rpg51

    rpg51 Member

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    Yea, my light is on all the time now. Doesn't bother me in the least. Just another little tiny light up there on the dash like the others.