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Re: [toyota-prius] Question about tire psi

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  • Levi Smith
    I go with the max pressure listed on the sidewall in the front and a couple psi less on the back. Levi ... [Non-text portions of this message have been
    Message 1 of 19 , Nov 5, 2009
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      I go with the max pressure listed on the sidewall in the front and a couple
      psi less on the back.

      Levi

      On Thu, Oct 29, 2009 at 4:29 PM, Lorraine cella <lorraine_cella@...>wrote:

      >
      >
      > What should tire psi be to achieve maximum MPG?
      > Thanks very much,
      > Lorraine
      >
      > [Non-text portions of this message have been removed]
      >
      >
      >


      [Non-text portions of this message have been removed]
    • dldorrance
      Me too. One caveat. The maximum pressure refers to the *cold* tire pressure. which translates as the pressure before the car is driven and will vary
      Message 2 of 19 , Nov 5, 2009
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        Me too. One caveat. The maximum pressure refers to the *cold* tire pressure. which translates as the pressure before the car is driven and will vary seasonly, as pressure is directly related to temperature.

        Dave '01 Prius

        --- In toyota-prius@yahoogroups.com, Levi Smith <LeviGSmith@...> wrote:
        >
        > I go with the max pressure listed on the sidewall in the front and a couple
        > psi less on the back.
        >
        > Levi
        >
        > On Thu, Oct 29, 2009 at 4:29 PM, Lorraine cella <lorraine_cella@...>wrote:
        >
        > >
        > >
        > > What should tire psi be to achieve maximum MPG?
        > > Thanks very much,
        > > Lorraine
        > >
        > > [Non-text portions of this message have been removed]
        > >
        > >
        > >
        >
        >
        > [Non-text portions of this message have been removed]
        >
      • deros1969
        I just got my Geico magazine. They had a article on Busting Mileage Myths . First let me say my tires are over-inflated at 40F38R. I quote from the article
        Message 3 of 19 , Nov 6, 2009
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          I just got my Geico magazine. They had a article on "Busting Mileage Myths". First let me say my tires are over-inflated at 40F38R.

          I quote from the article "Over-inflating tire, which some claim can improve milage, also can make tires more susceptible to road hazards."

          Just a point of interest on over-inflation.
        • Levi Smith
          You ve got tires that aren t rated for 40psi? That seems to be more of a rarety these days... My 5 sets of Impreza and Prius tires are all rated for 44 or
          Message 4 of 19 , Nov 6, 2009
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            You've got tires that aren't rated for 40psi? That seems to be more of a
            rarety these days... My 5 sets of Impreza and Prius tires are all rated for
            44 or 51psi...

            Levi

            On Fri, Nov 6, 2009 at 11:43 AM, deros1969 <deros1969@...> wrote:

            >
            >
            > I just got my Geico magazine. They had a article on "Busting Mileage
            > Myths". First let me say my tires are over-inflated at 40F38R.
            >
            > I quote from the article "Over-inflating tire, which some claim can improve
            > milage, also can make tires more susceptible to road hazards."
            >
            > Just a point of interest on over-inflation.
            >
            >
            >


            [Non-text portions of this message have been removed]
          • Cal Grandy
            Was always putting in 42 front and 40 rear but now that dealer takes it upon themselves to inflate with nitrogen they tell me I shouldn t mix regular air with
            Message 5 of 19 , Nov 6, 2009
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              Was always putting in 42 front and 40 rear but now that dealer takes it upon themselves to inflate with nitrogen they tell me I shouldn't mix regular air with it! Is this so?


              ---- deros1969 <deros1969@...> wrote:
              > I just got my Geico magazine. They had a article on "Busting Mileage Myths". First let me say my tires are over-inflated at 40F38R.
              >
              > I quote from the article "Over-inflating tire, which some claim can improve milage, also can make tires more susceptible to road hazards."
              >
              > Just a point of interest on over-inflation.
              >
            • Lee Hart
              ... SOME claim... CAN improve... CAN make more susceptible? This weasel-worded statement is guaranteed to be true... and also completely useless. Here s a more
              Message 6 of 19 , Nov 6, 2009
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                > "Over-inflating tire, which some claim can improve mileage, also can
                > make tires more susceptible to road hazards."

                SOME claim... CAN improve... CAN make more susceptible? This
                weasel-worded statement is guaranteed to be true... and also completely
                useless.

                Here's a more useful way to say it:

                Raising the inflation pressure lowers the rolling resistance. This has
                been verified by both informal and scientifically valid testing. The
                improvement is greatest for low pressures, and gets smaller as the
                pressure goes up. I.e. going from 30 to 35 psi is a bigger improvement
                than going from 40 to 45 psi, and going from 45 to 50 psi is even less.

                Raising the inflation pressure also increases the risk of road hazards.
                The higher the pressure, the more susceptible the tire is to damage from
                potholes, curbs, etc.

                This means there is a trade-off. You need to select the pressure that
                balances rolling resistance off against impact resistance.

                Car manufacturers in fact include a lot more factors in this balancing
                act; tire wear, ride comfort, noise, traction, handling, etc. In the
                end, low rolling resistance is all but ignored in favor of these other
                factors. That's why raising the tire pressure a little over the
                manufacturer's recommendation will give you lower rolling resistance
                (better gas mileage), without losing much in the other areas.
                --
                Lee A. Hart | Ring the bells that still can ring
                814 8th Ave N | Forget the perfect offering
                Sartell MN 56377 | There is a crack in everything
                leeahart earthlink.net | That's how the light gets in -- Leonard Cohen
              • Peter Blackford
                regular air is about 75% nitrogen anyway... watta crock he s trying to sell!
                Message 7 of 19 , Nov 6, 2009
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                  'regular air' is about 75% nitrogen anyway... watta crock he's trying to sell!

                  -----Original Message-----
                  >From: Cal Grandy <cal@...>
                  >Sent: Nov 6, 2009 12:01 PM
                  >To: toyota-prius@yahoogroups.com
                  >Subject: Re: [toyota-prius] Re: Question about tire psi
                  >
                  >Was always putting in 42 front and 40 rear but now that dealer takes it upon themselves to inflate with nitrogen they tell me I shouldn't mix regular air with it! Is this so?
                  >
                  >
                • Paul Lawler
                  ... Let me say that as long as your tires are inflated to a number less than or equal to the number on the sidewall of the tire, they are not OVER-inflated.
                  Message 8 of 19 , Nov 6, 2009
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                    On Nov 6, 2009, at 06:43 , deros1969 wrote:

                    > I just got my Geico magazine. They had a article on "Busting Mileage
                    > Myths". First let me say my tires are over-inflated at 40F38R.

                    Let me say that as long as your tires are inflated to a number less
                    than or equal to the number on the sidewall of the tire, they are not
                    "OVER-inflated."

                    > I quote from the article "Over-inflating tire, which some claim can
                    > improve milage, also can make tires more susceptible to road hazards."

                    Ditto.

                    > Just a point of interest on over-inflation.

                    Which is not what you are doing.
                  • Earle Jones
                    ... * OHMYGOD!! You re mixing air and nitrogen? Just FYI, air is 79% nitrogen, 20% oxygen, and 1% everything else -- CO2, argon, water vapor, etc. earle *
                    Message 9 of 19 , Nov 6, 2009
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                      On Nov 6, 2009, at 9:01 AM, Cal Grandy wrote:

                      > Was always putting in 42 front and 40 rear but now that dealer takes
                      > it upon themselves to inflate with nitrogen they tell me I shouldn't
                      > mix regular air with it! Is this so?

                      *
                      OHMYGOD!! You're mixing air and nitrogen?

                      Just FYI, air is 79% nitrogen, 20% oxygen, and 1% everything else --
                      CO2, argon, water vapor, etc.

                      earle
                      *
                      ________________________
                      Earle Jones 
                      380 Conil Way
                      Portola Valley CA 94028
                      Home: 650-854-1489
                      Cell: 650-269-0035
                      earle.jones@...
                    • Mark Binder
                      Since sunny sarasota is pretty much pothole-free, we have been running 44f/42r for years. Before we switched to nitrogen, we were refilling tires literally
                      Message 10 of 19 , Nov 7, 2009
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                        Since sunny sarasota is pretty much pothole-free, we have been running
                        44f/42r for years.



                        Before we switched to nitrogen, we were refilling tires literally every gas
                        fillup.but since we put in nitrogen, about three years ago, we have never
                        had to worry about the slightest tire deflation.



                        Mark





                        _____

                        From: toyota-prius@yahoogroups.com [mailto:toyota-prius@yahoogroups.com] On
                        Behalf Of Cal Grandy
                        Sent: Friday, November 06, 2009 12:01 PM
                        To: toyota-prius@yahoogroups.com
                        Subject: Re: [toyota-prius] Re: Question about tire psi





                        Was always putting in 42 front and 40 rear but now that dealer takes it upon
                        themselves to inflate with nitrogen they tell me I shouldn't mix regular air
                        with it! Is this so?

                        ---- deros1969 <deros1969@yahoo. <mailto:deros1969%40yahoo.com> com> wrote:
                        > I just got my Geico magazine. They had a article on "Busting Mileage
                        Myths". First let me say my tires are over-inflated at 40F38R.
                        >
                        > I quote from the article "Over-inflating tire, which some claim can
                        improve milage, also can make tires more susceptible to road hazards."
                        >
                        > Just a point of interest on over-inflation.
                        >





                        [Non-text portions of this message have been removed]
                      • Karl H
                        OK, what is the final decider? The door says 35PSI. IIRC, the (Lack-Of-)Integrety s said 42PSI. The Pirelli Cinturato P5 s on my car now say 44PSI. Can I
                        Message 11 of 19 , Nov 8, 2009
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                          OK, what is the final decider?

                          The door says 35PSI.

                          IIRC, the (Lack-Of-)Integrety's said 42PSI.

                          The Pirelli Cinturato P5's on my car now say 44PSI.

                          Can I SAFELY run 44/42?

                          --- In toyota-prius@yahoogroups.com, "deros1969" <deros1969@...> wrote:
                          >
                          > I just got my Geico magazine. They had a article on "Busting Mileage Myths". First let me say my tires are over-inflated at 40F38R.
                          >
                          > I quote from the article "Over-inflating tire, which some claim can improve milage, also can make tires more susceptible to road hazards."
                          >
                          > Just a point of interest on over-inflation.
                          >
                        • kevin
                          The air you breath is mostly nitrogen. Same stuff you put in the tire using a compressor. So why couldn t you add an oxygen - nitrogen mixture into a tire
                          Message 12 of 19 , Nov 9, 2009
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                            The air you breath is mostly nitrogen. Same stuff you put in the tire using a compressor.

                            So why couldn't you add an oxygen - nitrogen mixture into a tire that has nitrogen?

                            K




                            ________________________________
                            From: Cal Grandy <cal@...>
                            To: toyota-prius@yahoogroups.com
                            Sent: Fri, November 6, 2009 9:01:27 AM
                            Subject: Re: [toyota-prius] Re: Question about tire psi


                            Was always putting in 42 front and 40 rear but now that dealer takes it upon themselves to inflate with nitrogen they tell me I shouldn't mix regular air with it! Is this so?

                            ---- deros1969 <deros1969@yahoo. com> wrote:
                            > I just got my Geico magazine. They had a article on "Busting Mileage Myths". First let me say my tires are over-inflated at 40F38R.
                            >
                            > I quote from the article "Over-inflating tire, which some claim can improve milage, also can make tires more susceptible to road hazards."
                            >
                            > Just a point of interest on over-inflation.
                            >







                            [Non-text portions of this message have been removed]
                          • StevenC
                            I have a 2008 and have run with 42/20 psi from the beginning, and had the tires rotated as recommended. I had a problem with cupping and road noise and had to
                            Message 13 of 19 , Dec 9, 2009
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                              I have a 2008 and have run with 42/20 psi from the beginning, and had the tires rotated as recommended. I had a problem with cupping and road noise and had to replace them prematurely. The supposed mileage savings is not worth the cost of tires early than need be to me. I will stick with Toyota recommeded pressure.


                              --- In toyota-prius@yahoogroups.com, kevin <shdrdr@...> wrote:
                              >
                              > The air you breath is mostly nitrogen. Same stuff you put in the tire using a compressor.
                              >
                              > So why couldn't you add an oxygen - nitrogen mixture into a tire that has nitrogen?
                              >
                              > K
                              >
                              >
                              >
                              >
                              > ________________________________
                              > From: Cal Grandy <cal@...>
                              > To: toyota-prius@yahoogroups.com
                              > Sent: Fri, November 6, 2009 9:01:27 AM
                              > Subject: Re: [toyota-prius] Re: Question about tire psi
                              >
                              >
                              > Was always putting in 42 front and 40 rear but now that dealer takes it upon themselves to inflate with nitrogen they tell me I shouldn't mix regular air with it! Is this so?
                              >
                              > ---- deros1969 <deros1969@yahoo. com> wrote:
                              > > I just got my Geico magazine. They had a article on "Busting Mileage Myths". First let me say my tires are over-inflated at 40F38R.
                              > >
                              > > I quote from the article "Over-inflating tire, which some claim can improve milage, also can make tires more susceptible to road hazards."
                              > >
                              > > Just a point of interest on over-inflation.
                              > >
                              >
                              >
                              >
                              >
                              >
                              >
                              >
                              > [Non-text portions of this message have been removed]
                              >
                            • Peter Shulman
                              I think the big problem with “air” is the source. Gas stations, quick mart stores and the like don’t have a drying column on their compressors (unlike
                              Message 14 of 19 , Dec 9, 2009
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                                I think the big problem with “air” is the source. Gas stations, quick mart stores and the like don’t have a drying column on their compressors (unlike the nitrogen fill stations) and their air contains a lot of moisture. The larger the holding tank on the compressor the more water vapor. The greater the amount of water in a tire, the greater the variation in pressure with temperature. Of course, if the compressor tank is drained regularly water vapor can be minimized. But, that never happens often enough in my experience; just vent the hose into the air and you can see the vapor coming out on most pumps. Of course, if one is in AZ or another dry state this is much less of a problem.



                                [Non-text portions of this message have been removed]
                              • Jim Saklad
                                ... The owner. ... With most tires, yes. -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Jim Saklad
                                Message 15 of 19 , Dec 9, 2009
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                                  > OK, what is the final decider?

                                  The owner.

                                  > Can I SAFELY run 44/42?

                                  With most tires, yes.

                                  --
                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                  Jim Saklad mailto:jimdoc@...
                                • trashcan
                                  Did you ever think about getting 4 - wheel alignment? I run 42-40, and make sure my alignment is in. I have no problems with the OEM tires.
                                  Message 16 of 19 , Dec 9, 2009
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                                    Did you ever think about getting 4 - wheel alignment?

                                    I run 42-40, and make sure my alignment is in. I have no problems with
                                    the OEM tires.

                                    StevenC wrote:
                                    >
                                    >
                                    > I have a 2008 and have run with 42/20 psi from the beginning, and had
                                    > the tires rotated as recommended. I had a problem with cupping and
                                    > road noise and had to replace them prematurely. The supposed mileage
                                    > savings is not worth the cost of tires early than need be to me. I
                                    > will stick with Toyota recommeded pressure.
                                    >
                                    > --- In toyota-prius@yahoogroups.com
                                    > <mailto:toyota-prius%40yahoogroups.com>, kevin <shdrdr@...> wrote:
                                    > >
                                    > > The air you breath is mostly nitrogen. Same stuff you put in the
                                    > tire using a compressor.
                                    > >
                                    > > So why couldn't you add an oxygen - nitrogen mixture into a tire
                                    > that has nitrogen?
                                    > >
                                    > > K
                                    > >
                                    > >
                                    > >
                                    > >
                                    > > ________________________________
                                    > > From: Cal Grandy <cal@...>
                                    > > To: toyota-prius@yahoogroups.com <mailto:toyota-prius%40yahoogroups.com>
                                    > > Sent: Fri, November 6, 2009 9:01:27 AM
                                    > > Subject: Re: [toyota-prius] Re: Question about tire psi
                                    > >
                                    > >
                                    > > Was always putting in 42 front and 40 rear but now that dealer takes
                                    > it upon themselves to inflate with nitrogen they tell me I shouldn't
                                    > mix regular air with it! Is this so?
                                    > >
                                    > > ---- deros1969 <deros1969@yahoo. com> wrote:
                                    > > > I just got my Geico magazine. They had a article on "Busting
                                    > Mileage Myths". First let me say my tires are over-inflated at 40F38R.
                                    > > >
                                    > > > I quote from the article "Over-inflating tire, which some claim
                                    > can improve milage, also can make tires more susceptible to road hazards."
                                    > > >
                                    > > > Just a point of interest on over-inflation.
                                    > > >
                                    > >
                                    > >
                                    > >
                                    > >
                                    > >
                                    > >
                                    > >
                                    > > [Non-text portions of this message have been removed]
                                    > >
                                    >
                                    >
                                  • Tom Holly
                                    ... Karl, as you point out, recommended tire pressure depends on the tire. So, a safe tire pressure depends on the tire. The max is 44 for Cinturato, so 44/42
                                    Message 17 of 19 , Dec 10, 2009
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                                      On Sun, Nov 8, 2009 at 7:11 AM, Karl H <joes_morgue@...> wrote:

                                      >
                                      >
                                      > OK, what is the final decider?
                                      >
                                      > The door says 35PSI.
                                      >
                                      > IIRC, the (Lack-Of-)Integrety's said 42PSI.
                                      >
                                      > The Pirelli Cinturato P5's on my car now say 44PSI.
                                      >
                                      > Can I SAFELY run 44/42?
                                      >
                                      >
                                      Karl, as you point out, recommended tire pressure depends on the tire.
                                      So, a safe tire pressure depends on the tire. The max is 44 for Cinturato,
                                      so
                                      44/42 should be okay for that tire.


                                      [Non-text portions of this message have been removed]
                                    • Paul Lawler
                                      ... Your posterior and your wallet. ... Indeed it does. If you want a softer ride (at the expense of mileage and tire life) choose this one. ... No, they said
                                      Message 18 of 19 , Dec 10, 2009
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                                        On Dec 10, 2009, at 09:52 , Tom Holly wrote:

                                        > On Sun, Nov 8, 2009 at 7:11 AM, Karl H <joes_morgue@...> wrote:
                                        >
                                        >> OK, what is the final decider?

                                        Your posterior and your wallet.

                                        >> The door says 35PSI.

                                        Indeed it does. If you want a softer ride (at the expense of mileage and tire life) choose this one.

                                        >> IIRC, the (Lack-Of-)Integrety's said 42PSI.

                                        No, they said 44 psi

                                        >> The Pirelli Cinturato P5's on my car now say 44PSI.
                                        >>
                                        >> Can I SAFELY run 44/42?

                                        Of course. That's what the tires are rated for.
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