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Tyre Pressure

Discussion in 'Gen 3 Prius Fuel Economy' started by GoMetricToday, Feb 1, 2011.

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  1. GoMetricToday

    GoMetricToday 42 is the answer to the ultimate question.

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    Well I increased my tyre pressure this morning to 275 kPa. Almost immediately I was getting 4.7 L/100 km in city driving. I have never understood why car manufactures seem to under-inflate tyres. Don't they know that people would save so much money in petrol if they would just increase the tyre pressure to begin with.? :D
     
    #1 GoMetricToday, Feb 1, 2011
  2. mainerinexile

    mainerinexile No longer in exile!

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    My tire store guy whom I trust says that automakers recommend low tire pressures for that squishy soft ride that drivers seem to want, and that the tires manufacturers don't disagree because they know that tires wear out faster when under-inflated so they sell more tires. Seems like a reasonable, if unjustifiable, explanation to me. Personally, I run 42/40 psi on the Prius, and 38/38 on my Tacoma.
     
    #2 mainerinexile, Feb 1, 2011
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  3. stream

    stream Senior Member

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    Despite your user id, most folks on this board have no idea what your numbers represent vs. something they can relate to. ;)
     
    #3 stream, Feb 1, 2011
  4. GoMetricToday

    GoMetricToday 42 is the answer to the ultimate question.

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    Oh well that is ok. LOL. I just use what I am used to and what is easier for me to understand. :rockon:
     
    #4 GoMetricToday, Feb 1, 2011
  5. F8L

    F8L Protecting Habitat & AG Lands

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    Unfortunately that is not a great way to get your point across. I see similar issues with ebonics and those who do not wish to learn correct English. lol
     
    #5 F8L, Feb 1, 2011
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  6. stream

    stream Senior Member

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    LMAO... :p
     
    #6 stream, Feb 1, 2011
  7. GoMetricToday

    GoMetricToday 42 is the answer to the ultimate question.

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    LOL.

    Here is something that might help. LOL

    Online conversion of weights and measures, measurement conversion.

    Just using what 95% of the rest of the world uses. Enjoy. ;)
     
    #7 GoMetricToday, Feb 1, 2011
  8. stream

    stream Senior Member

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    But--probably 95% of the folks on this forum are from US and don't use the metric system, so your comment was useful for a full 5% of the audience. :eek:
     
    #8 stream, Feb 1, 2011
  9. JimN

    JimN Let the games begin!

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    IMO you're still running too soft. I'd bump up to at least 300 (easy to see on my gauge) or 310 or max sidewall pressure.
     
    #9 JimN, Feb 1, 2011
  10. cwerdna

    cwerdna Senior Member

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    #10 cwerdna, Feb 1, 2011
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  11. GoMetricToday

    GoMetricToday 42 is the answer to the ultimate question.

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    I had thought about going to 300 kPa, but I am such a creature of comfort that I know for my liking it would make it too rough. I had my tyre pressure at 300 kPa in my Gen II Insight and found it was too harsh for me. So I dropped it down to 275 kPa. I appreciate your suggestion. It is always nice to get helpful information. Thank you. :D
     
    #11 GoMetricToday, Feb 2, 2011
  12. DanMode

    DanMode Brooklyn Prius Guy

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    I think no matter what I do now in my daily life, I will compare it to how many teaspoons per mile I'd get! :D
     
    #12 DanMode, Feb 2, 2011
  13. SparkieBlues

    SparkieBlues New Member

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    I am part of that 5% and find it very useful. :)
     
    #13 SparkieBlues, Feb 2, 2011
  14. DarrenG

    DarrenG Member

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    And even though the UK is now metric for most things, I only understand PSI in respect of tyre pressures and have never heard of kPA.
     
    #14 DarrenG, Feb 4, 2011
  15. Teakwood

    Teakwood Member

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    If I had "tyres" on my car, I might measure the pressure in kPa, but since I have only "tires" on my car, I measure the pressure in PSI.
     
    #15 Teakwood, Feb 4, 2011
  16. DarrenG

    DarrenG Member

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    Tire in American English or Tyre in proper English ;)

    And in the UK, where we speak Queen's English, it's PSI not kPa with attempts to move to Bar.

    Why do we have to have so many different measurements for the same thing!
     
    #16 DarrenG, Feb 4, 2011
  17. Teakwood

    Teakwood Member

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    Beats me, especially since 1 Pascal = 145.04×10−6 PSI.
    Oh, yeah. It is very important to be measuring tire pressure in units that are that fine.:huh:
     
    #17 Teakwood, Feb 4, 2011
  18. GoMetricToday

    GoMetricToday 42 is the answer to the ultimate question.

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    DarrenG, you are correct about the spellings. My Paternal Grandmother, Grandfather and Father are British and insisted that my sister and I learned as my Grandmother calls it "Proper English". Though I am American, to this day I still use proper English. As I said in earlier posts I use what I am used to. As for kPa (metric) that is pressure in kiloPascals. The Bar is an antiquated measure for pressure was more commonly used for atmospheric pressure rather than tyre pressure. :rockon:
     
    #18 GoMetricToday, Feb 5, 2011
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  19. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    As long as we're discussing conversions: There's a Chevy Cruze ad in Friday's Vancouver Province, proclaiming it gets:

    "50 mpg HWY"

    No explanation that the calculation is very likely miles per imperial gallon, which is 5/4th's of a US gallon (5 quarts, 160 oz per gallon, vs the US 4 quart, 128 oz).

    Now, gas has been sold in litres in Canada for about 30~40 years now, but for some reason Candian car dealers still cherish the imperial gallon...
     
    #19 Mendel Leisk, Feb 5, 2011
  20. F8L

    F8L Protecting Habitat & AG Lands

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    No thanks. I'll continue to use the system that the majority of people in my country and this forum use. It's better than coming across like a weirdo who is fascinated with being different. :D
     
    #20 F8L, Feb 5, 2011
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