Help me with correct tire pressure (after change of tire size)

Discussion in 'Gen 2 Prius Main Forum' started by pnerd, Jul 12, 2011.

  1. pnerd

    pnerd Junior Member

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    Hi all,
    I have a 2006 Prius with stock 16" alloy wheels.
    The stock tires were Bridgestone Turanza 195/55 R16.
    I simply always pumped to the upper-range of the recommendation on the sticker on the driver's door frame. Think it was about 38 PSI.

    I recently had to change them all at once, and didn't have the luxury of choosing the exact same model or size...

    The shop put these on:
    Yokohama DNA dB Decibel 205/50 R16 87V

    The shop pumped them to a pressure that I forgot... that was about 5 months ago.
    Now I feel like topping up the tires, but I don't know what pressure to put in...

    Hope to get some help here...
    Should it be higher or lower than the pressure for the stock tires?
     
  2. ursle

    ursle Gas miser

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    Some run 42 front 40 rear
    some higher some lower
    I run 36 all around, found the center of the tires wearing to fast at 38-40
    ymmv
     
  3. pnerd

    pnerd Junior Member

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    Thanks, but what size tires are you referring to?
    Or do you think that my change in tire size doesn't affect correct pressure?

    Something I found googling: Google Answers: Car tyre pressure
     
  4. F8L

    F8L Protecting Habitat & AG Lands

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    Why didn't they put the OEM size tire back on? The dB Super E-Spec comes in a 195/55/16.

    Either way, the pressure is up to you. I've ran up to 50psi on my 185/65/15 dB Super E-specs but I think I settled with 44/42psi and I was happy with that.
     
  5. snead_c

    snead_c Jam Ma's Car

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    Consider the door sticker as your baseline. Use it with the listed approved tire sizes and corresponding pressures and you will be safe. If you're trying to improve mpg and are willing to sacrifice comfort gradually inch up the pressures by 2 lbs above the stickers and evaluate comfort and repeat as desired. You do not ever want to go above the pressures listed on the tire sidewalls as max pressure. Tire performance and wear patterns are affected by over as well as under inflation. Be sure to check inflation when tires are "cold" ( out of the sun and not run for at least 3 hours.) First thing in the AM is a good practice. Check your air pressure every few weeks and especially before seasonal temperature changes. Invest in a good pressure guage which can be found at your local auto parts store, Wally World, or a place like Amazon.com There are often useful consumer reviews on the web that may steer you away from junk like most pencil types.
     
  6. JimN

    JimN Let the games begin!

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    There is no "correct" tp. It depends on the tire, the load, & what you want. Harder tires will handle a higher load & wear slower. IMO pump in max sidewall pressure.
     
  7. David Beale

    David Beale Senior Member

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    In general, a larger tyre will require less pressure for the same load, but it also depends on the tyre construction.

    In your case I wouldn't worry much about it. Use the same pressure you were using before. It it rides too rough, decrease pressure a bit. Do note that the recommended pressure for a Prius is slightly lower in the rear than in the front.

    To actually figure out the "correct" pressure you need a glass plate on the roadway and a high speed camera to see the tread on the plate as you drive over it at speed. Or you can run them at some initial pressure and see how they wear. Neither method is very satisfactory for one case such as yours. Hence my recommendation above.
     
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