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What tire pressure are you running at?

Discussion in 'Prius c Fuel Economy' started by Prius Maximus, Mar 23, 2012.

  1. vvillovv

    vvillovv Senior Member

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    I finally got around to finding a pump and adding air a week ago. I tried for 40 all around but only got 40 in one and 39 in the other three.

    As far as traction on gravel, I'd think there is really nothing one can do to get better traction on gravel unless one has tracks or something similar to those things the cats use to groom ski trails.
     
  2. robert c

    robert c Junior Member

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    I run 40 psi all tires.
     
  3. ls40095

    ls40095 Junior Member

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    I currently have a 2012 C and also a 2013 I just finished. The 2012 we use as our main transportation. When I purchased it and rebuilt it last year, I pitched the garbage Bridgestone tires and replaced them with Michelin energy savers. Regardless of tire, I find the ride harsh with anything more than 33 (especially compared to gen 3) but I live in PA where our roads are crap. If I'm going on vacation, driving to Florida, I'm going to 40PSI
     
  4. Alexinnitro

    Alexinnitro New Member

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    You usually have diminishing results in performance the closer you get to the sidewall maximum. I usually run about 6 or 7 under the sidewall max. That usually offers a good comprise of performance and comfort.
     
  5. Dimitrij

    Dimitrij Active Member

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    Whereas it's true that nitrogen molecule is somewhat smaller than that of oxygen, the difference is minuscule; besides, air is 79% nitrogen. I do not believe there is a great difference in the thermal expansion coefficient either, but I might be wrong.

    I think the real problem with air that, apart from oxygen it contains CO2 and water vapor, so you have conditions that are conducive to faster corrosion: elevated temperature, slightly acidic environment, oxygen and water. Nitrogen at the tire temperatures is chemically inert towards metals, hence slower corrosion. Air pumps at gas stations are supposed to dehumidify air, but if they do, that I can't know.
     
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  6. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    It might be easier to regard nitrogen fill as "oxygen-free" fill.

    The only time I get nitrogen is with Costco tire installs. And that lasts about 2~3 kms: since they refuse to put in more than manufacturer's recommendation, I typically pull in at a nearby Chevron (still offering free air!), put more regular air in, and swap out the green tire caps for black.
     
  7. With everything so solid frozen over my tire pressure went down into the low-mid 30s all winter, which is at the manufacturer's recommended pressure.

    Summer is coming quick, and ice is melting everywhere, so I just adjusted mine again, 45 psi in the front, 43 psi in the back, and the max. sidewall of my tires is 51.
     
  8. Dimitrij

    Dimitrij Active Member

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    Why is everyone keeping the front tires @ 2 pounds higher than the rear ones?
     
  9. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    In the driver's door there's a plaque with recommended pressures: fronts are 2 psi higher.

    That said, I set them all the same: simplifies rotation.
     
  10. hieronymous

    hieronymous Member

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    For the usual reason - there is more weight on the front wheels than on the rear ones (61%, 39%); being front wheel drive, the ICE, motors and transmission are all at the front, and while the HV battery is under the back seat, it is small compared to an EV battery e.g. Leaf, so much lighter.

    GT-I9300 ?
     
    #50 hieronymous, Mar 11, 2015
    Last edited: Mar 11, 2015
  11. Dimitrij

    Dimitrij Active Member

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    ^ 61%; 39% and that's how you know that Prius c ain't no Subaru o_O
     
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  12. mahout

    mahout Active Member

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    Strictly dealer sales gimmick just like those paint sealants etc. the only advantage of pure nitrogen is less pressure buildup with temperature and almost no effect on street driving. Air is 81% nitrogen and pure nitrogen is only useful on racing vehicles .The profile of the tread is set by pressure, not the gas that yields the pressure. And yes, you might go a week longer before the pressure drops due to migration of the molecules through the tire wall - thats true, BTW. but no loss of pressure is bogus. we do use N2 in our race cars but not in street cars; its a complete waste of money. Just for fun ask the SAE to back up your pitch.
     
  13. Paranormal Rob

    Paranormal Rob Active Member

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    Wrong

    Posted via the PriusChat mobile app.
     
  14. ztanos

    ztanos All-around Geek!

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    Wow... Paranormal Rob, resurrecting ghosts and dead threads. :D
     
  15. Paranormal Rob

    Paranormal Rob Active Member

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    It was on top of the section I looked in. If its old, delete it

    Posted via the PriusChat mobile app.
     
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