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Thread: Tires & Pressure OEM recommendations U.S. (35) vs. Japan (39 PSI)

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    Tires & Pressure OEM recommendations U.S. (35) vs. Japan (39 PSI)

    Both the u.S. and Japan Mirage manuals specifies 165/65R14 tires, but does anyone know why the u.S. manual specifies 35psi whereas the Japanese manual specifies 39psi?



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    Interesting find.

    Normally you'd find a higher pressure recommended for heavier weight or sustained high speed driving. Neither of those really apply.

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        click to view fuel log View my fuel log 2014 Mirage base ES 1.2 manual: 54.0 mpg (US) ... 23.0 km/L ... 4.4 L/100 km ... 64.9 mpg (Imp)


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    maybe because US streets are s**tty in comparison to their Japanese counterparts?

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        click to view fuel log View my fuel log 2014 Mirage DE 1.2 manual: 47.8 mpg (US) ... 20.3 km/L ... 4.9 L/100 km ... 57.3 mpg (Imp)


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    You're probably right, Donut

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    The surface of U.S. Roads is different types of Tarmac, on top of that we have more wear on our streets.
    To add insult to injury we have the Right side driving standard which results in quicker turns at intersections and over inflated tires won't do well on ANY of those conditions. There's also the factor of Japanese roads containing FAR more traffic than the U.S. counterparts (in most cities at least.)
    Sea level, and air pressure are also a factor in this as well.
    The psi recommendation doesn't take into account geographical location, and weather patterns though. Honestly it will vary a few PSI depending on where you live; but that's something you come to find out the more you drive cars, and have wheels on the road.

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        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 36.2 mpg (US) ... 15.4 km/L ... 6.5 L/100 km ... 43.5 mpg (Imp)


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    Just putting in my 2 cents. When I got my car, it had 36 psi in the tyres.
    Yet the tyre card says for the maximum speed you can legally go in AUS, put 32 psi

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    Senior Member Ares's Avatar
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    How about temps? Maybe Japan does not get hot enough for the gasses inside the tires to expand?

    OR they don't drive far enough for the gasses to heat up and expand... Either way, I say it has something to do with temps...

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    although the temperature could be a reason, it doesn't seem to explain these big differences in suggested tire pressure.

    let the volume in the tire be approximately constant, the temperature must then be higher by ~11% to bring the pressure up from 35 to 39 psi.

    Do you have information about how much tires heat up during a drive?

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage DE 1.2 manual: 47.8 mpg (US) ... 20.3 km/L ... 4.9 L/100 km ... 57.3 mpg (Imp)


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    My Mirage manual gaveinstructions for pairing the phone using buttons that don't exist on my car, and then using voice commands, which the car doesn't accept. Point being that you have to take manuals -especially from foreign manufacturers with a grain of salt.

    If you want to have some fun, try reading a Denon manual. They make no sense and haven't for years.

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    Mitsu US stated that the 35psi recommendation are for their U.S. vehicles in compliance with NHTSA/DOT regulations.



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