1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Tyre Pressure

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

  1. GoMetricToday

    GoMetricToday 42 is the answer to the ultimate question.

    Joined:
    Jan 10, 2011
    64
    6
    9
    Location:
    Erwin, TN
    Vehicle:
    2010 Prius
    Model:
    II
    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
     
  2. mainerinexile

    mainerinexile No longer in exile!

    Joined:
    Mar 14, 2010
    403
    73
    0
    Location:
    Maine
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    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.
     
    1 person likes this.
  3. stream

    stream Senior Member

    Joined:
    May 12, 2008
    2,977
    452
    14
    Location:
    Long Island, NY
    Vehicle:
    2010 Prius
    Model:
    V
    Despite your user id, most folks on this board have no idea what your numbers represent vs. something they can relate to. ;)
     
  4. GoMetricToday

    GoMetricToday 42 is the answer to the ultimate question.

    Joined:
    Jan 10, 2011
    64
    6
    9
    Location:
    Erwin, TN
    Vehicle:
    2010 Prius
    Model:
    II
    Oh well that is ok. LOL. I just use what I am used to and what is easier for me to understand. :rockon:
     
  5. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,081
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    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
     
    1 person likes this.
  6. stream

    stream Senior Member

    Joined:
    May 12, 2008
    2,977
    452
    14
    Location:
    Long Island, NY
    Vehicle:
    2010 Prius
    Model:
    V
    LMAO... :p
     
  7. GoMetricToday

    GoMetricToday 42 is the answer to the ultimate question.

    Joined:
    Jan 10, 2011
    64
    6
    9
    Location:
    Erwin, TN
    Vehicle:
    2010 Prius
    Model:
    II


    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. ;)
     
  8. stream

    stream Senior Member

    Joined:
    May 12, 2008
    2,977
    452
    14
    Location:
    Long Island, NY
    Vehicle:
    2010 Prius
    Model:
    V
    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:
     
  9. JimN

    JimN Let the games begin!

    Joined:
    Nov 26, 2006
    7,028
    1,116
    0
    Location:
    South Jersey
    Vehicle:
    2010 Prius
    Model:
    V
    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.
     
  10. cwerdna

    cwerdna Senior Member

    Joined:
    Sep 4, 2005
    12,544
    2,123
    1
    Location:
    SF Bay Area, CA
    Vehicle:
    2006 Prius
    1 person likes this.
  11. GoMetricToday

    GoMetricToday 42 is the answer to the ultimate question.

    Joined:
    Jan 10, 2011
    64
    6
    9
    Location:
    Erwin, TN
    Vehicle:
    2010 Prius
    Model:
    II
    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
     
  12. DanMode

    DanMode Brooklyn Prius Guy

    Joined:
    May 31, 2009
    98
    21
    0
    Location:
    Brooklyn, NY
    Vehicle:
    2010 Prius
    Model:
    III
    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
     
  13. SparkieBlues

    SparkieBlues New Member

    Joined:
    Jan 16, 2011
    66
    11
    0
    Location:
    Bangkok
    Vehicle:
    2010 Prius
    Model:
    N/A
    I am part of that 5% and find it very useful. :)
     
  14. DarrenG

    DarrenG Member

    Joined:
    Oct 18, 2009
    138
    11
    0
    Location:
    Hampshire, UK
    Vehicle:
    2006 Prius
    Model:
    N/A
    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.
     
  15. Teakwood

    Teakwood Member

    Joined:
    Jun 23, 2010
    491
    73
    0
    Location:
    New Mexico
    Vehicle:
    2010 Prius
    Model:
    II
    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.
     
  16. DarrenG

    DarrenG Member

    Joined:
    Oct 18, 2009
    138
    11
    0
    Location:
    Hampshire, UK
    Vehicle:
    2006 Prius
    Model:
    N/A
    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!
     
  17. Teakwood

    Teakwood Member

    Joined:
    Jun 23, 2010
    491
    73
    0
    Location:
    New Mexico
    Vehicle:
    2010 Prius
    Model:
    II
    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:
     
  18. GoMetricToday

    GoMetricToday 42 is the answer to the ultimate question.

    Joined:
    Jan 10, 2011
    64
    6
    9
    Location:
    Erwin, TN
    Vehicle:
    2010 Prius
    Model:
    II

    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:
     
    Andy Truzzi likes this.
  19. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    55,413
    38,648
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    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...
     
  20. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,081
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    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