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Yes another Tire Pressure question

Discussion in 'Gen 2 Prius Main Forum' started by treehggr, Aug 28, 2007.

  1. treehggr

    treehggr New Member

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    Ok, what exactly is considered cold pressure? Is this just the pressure after not driving the car for a while, say in the morning? I feel that my pressure of 42/40 may be a little high due to the heat here in AZ. The reason I ask is that I check my pressure in the morning and the ambient temp in our garage is usually between 80-90 degrees. To me that doesn't seem like a cold pressure. Am I worrying for no reason? I have yet to check my pressure after a day of driving but I'm willing to bet that my 42/40 is closer to 50/48 at the end of the day in this heat. Is this bad for the tires or even safe for that matter? Should I make any changes in how I check/adjust my pressure?
     
  2. hobbit

    hobbit Senior Member

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    At 1 psi for every 10 degrees rise, 8 more psi would be quite the
    temp delta. Besides, the harder you run 'em the less heat they tend
    to build up on the road...
    .
    _H*
     
  3. krazymadmann

    krazymadmann New Member

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    Yes, cold pressure refers to the tires being cold from not driving on them, if your ambiant temp is 80 then that is your cold pressure, be sure to check them anytime your climate changes considerably as they will be low in the winter if you don't. We have been around 80 here as well, and I set my pressure a bit higher than what you might consider normal. 52/50 front/rear, with no strange signs of wear at 15,000 miles.

    madman
     
  4. treehggr

    treehggr New Member

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    Hobbit, It has been over 106 lately which just had me worried. You can fry an egg no problem on the pavement here. Just want to make sure I was in a safe threshold.

    Madman, Thanks for the info. "Cold" had me a little confused. The word "Cold" is very rarely spoken around here...lol
     
  5. Danny Hamilton

    Danny Hamilton Active Member

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    <div class='quotetop'>QUOTE(treehggr @ Aug 28 2007, 04:24 PM) [snapback]503435[/snapback]</div>
    Keep in mind that under-inflation carries a higher risk of blowout than over-inflation. Adjusting your tires to the Toyota recommended 33psi out in 106 degree heat after driving a long distance (not cold pressure) could have serious repercussions.

    http://money.cnn.com/2000/08/09/news/firestone_recall/

    "The move comes amid intense pressure from major tire retailers, safety advocates and government regulators to pull the tires after receiving reports that the tires may be linked to as many as 46 deaths and hundreds of accidents."

    "The vast majority of incidents are in the southern states of Arizona, California, Florida and Texas, which suggests there may be a direct correlation between heat and tire performance," Crigger said. "Most of the incidents we have reviewed indicate improper maintenance or damage to the tires, which is often caused by under-inflation of tires. Under-inflated operation of any tire generates excessive heat, which can lead to tire failure."
     
  6. treehggr

    treehggr New Member

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    Thanks Danny, I appreciate the help.
     
  7. brad34695

    brad34695 New Member

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    <div class='quotetop'>QUOTE(madman @ Aug 28 2007, 05:12 PM) [snapback]503425[/snapback]</div>

    I'm glad to see there is another 50+ psi guy out here. Just yesterday my mechanic (who I generally like) lectured me after changing my oil and giving me a tire rotation for having my tires too inflated. He thought I was crazy for having tire pressures in the 50's because he told me that would give me uneven center tire wear. Meaning that the middle of the tire would wear excessive and cause premature replacement of my tires. He gave my car back to me at 35 psi!!!

    Again I like the guy, but I don't have to agree with him. I am going to a neighborhood gas station in the AM and get them back in the 50's. I drove them since yesterday at 35 psi and I could tell the excessive rolling resistance and not having as effective P&G.
     
  8. tochatihu

    tochatihu Senior Member

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    Waiting 6 years for a photo of Prius radial tires, with ANY inflation pressure, with excess center tread wear.

    Still waiting
     
  9. qbee42

    qbee42 My other car is a boat

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    <div class='quotetop'>QUOTE(treehggr @ Aug 28 2007, 05:24 PM) [snapback]503435[/snapback]</div>
    We are at 61 here, which is still a lot hotter than what we get in the winter. 106!?! - sheesh! B)

    Tom
     
  10. bobdavisnpf

    bobdavisnpf Member

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    51 front, 48 rear, no signs of center wear or loss of traction/control.
     
  11. gazz

    gazz Member

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    <div class='quotetop'>QUOTE(qbee42 @ Aug 29 2007, 10:43 PM) [snapback]504144[/snapback]</div>
    All you running at 50+ psi what is your max pressure, the reason I ask is that my tires do not have a max pressure so I am running them at 40/42. Are you running them over max pressure?
     
  12. qbee42

    qbee42 My other car is a boat

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    <div class='quotetop'>QUOTE(gazz @ Aug 31 2007, 08:27 AM) [snapback]504818[/snapback]</div>
    Ha, no, I should have been more clear. When I said we are at 61, I was talking about 61 degrees F. A lot of the country has had very hot weather, but not in our area. As for your question, I run my tires well below the maximum listed pressure.

    Tom
     
  13. FireEngineer

    FireEngineer Active Member

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    <div class='quotetop'>QUOTE(treehggr @ Aug 28 2007, 04:24 PM) [snapback]503435[/snapback]</div>
    That's what we did for breakfast before we left after installing your EBH. Just to let you know, I set my tires at 64/62 before leaving Chicago, betcha they were higher when we were there. Drove just fine, soon as those roads get finished you'll have some good gliding.

    Wayne
     
  14. PA Prius

    PA Prius Active Member

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    I would be glad to hear of any negative effects that anyone has experieced when having the tires inflated significantly above recommended maximum. The first thing people usually say is "blowout." Has that ever happened?

    PA P
     
  15. treehggr

    treehggr New Member

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    <div class='quotetop'>QUOTE(qbee42 @ Aug 29 2007, 08:43 PM) [snapback]504144[/snapback]</div>
    Yeah the desert sucks. We have been reaching record highs for this time of year. This week has been close to 110 everyday. :eek:


    <div class='quotetop'>QUOTE(FireEngineer @ Aug 31 2007, 11:12 AM) [snapback]505038[/snapback]</div>
    I just bumped my pressure up to 44/42 from 42/40 and I think I'm noticing a small difference. I got to say though, that EBH kicks some major nice person. I have about 205 mi on this tank and I'm sitting at 68.2 mpg. Couldn't be happier.
     
  16. etyler88

    etyler88 etyler88

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    I got mine at 60 psi. Sidewall max say 44 psi. I always wear out my corners first. If the same guy makes the max psi number as writes the tire treadlife "warranty" - I'm not falling for it.
     
  17. msirach

    msirach Member

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    My wife's Prius is at 50psi. My Insight is at 70psi. Max pressure on both is 44 psi. Temps here have been around 100.
     
  18. PA Prius

    PA Prius Active Member

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    Well then, I bumped mine up to 48/46 this evening. I hit 75,000 miles this week. Nothing other than oil and filter changes, tires, steering column recall, and an occasional tank of gas.

    PA P
     
  19. BIGDGR

    BIGDGR New Member

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    Presently running 40/40 psi tire pressure. Temps are from 4 to 32 degrees and light snow on roads. So far traction seems fine. One change to my model. It is a 2009 touring 6. The choices only go to touring 4. Great info on this site!!!