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correct Tyre pressure for Corsa 1.2 Merit 5door

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  • [Corsa B 1993-2000] correct Tyre pressure for Corsa 1.2 Merit 5door

    Hi,

    Would greatly appreciate some help.

    Am having difficulty getting correct tyre pressure for my 1.2 Corsa Merit 5 door.

    The tyres on my 1996 1.2 5door Corsa Merit are 145/80 R13. My Corsa owners manual [P.234] only shows pressures for the following tyres, assuming I have a Z12XE engine with 32 front and 26 psi rear:

    155/80 R 13
    175/65 R 14
    185/55 R 15
    195/45 R 16
    205/40 R 17


    Does this mean I have the wrong tyres on my car? What should the tyre pressures be?
    No technical data label on driver's door frame. Chekd manual. Tyre pressures related to engine code and engine number [P.235].

    Why is this?

    Would [in theory] mean the tyres will wear down quicker as they are not as wide as listed and need a higher pressure [to maintain the tyres' shape] because of the car's weight on the narrower tyres?


    Thanks for advice,

    Max.

  • #2
    Tyre pressures for the 1996 1.2 are usually 27 front, 24 rear. Fully laden 30 front and 35 rear.

    I ran mine at 28 all round with no problems.

    If you want to check which engine post a photo of it.
    1972 Viva restoration thread - http://www.thecorsa.co.uk/projects-b....html#post1534

    Comment


    • #3
      The pressures are usually listed on the inside of the petrol tank access lid.

      Not sure if the sizes listed in the manual include a minimum width size or are just what OPEL fit as OEM.




      Should not the pressure be the same (as specified for the mass of the vehicle) regardless of the tyre size?

      'X' psi is still 'x' psi regardless of whether a 155 is fitted or a tractor tyre (if that were possible) to the vehicle in question

      or am I not understanding something fundemental???

      Comment


      • #4
        Tyre pressures vary according to the size of tyre and vehicle specifications, but I've usually found that the pressures listed aren't always the best in practical use. A bit of trial and error usually results in what actually works best.

        The B model fitted with the 8v engine (most 1996 models) prefers slightly lower pressures than those fitted with the 16v engines. They develop a tendency to pull to one side when the pressures are off.
        1972 Viva restoration thread - http://www.thecorsa.co.uk/projects-b....html#post1534

        Comment


        • #5
          Hi T.,

          Sorry for delay in replying. I looked at the corsa when it was parked and saw the front tyres more compressed than rear. Have pumped them to 27 and 24psi and see how it goes.

          Thanks again for t info.

          Regs, Max.

          Comment


          • #6
            Hi Z.,

            Sorry for delay in responding.

            No label on tank access lid or at drivers door frame.

            Yeah. U are right. Pressures the same regardless of tyre size. My knowledge of physics is v.limited.

            Thanks for info.

            Regs, Max.

            Comment


            • #7
              Hi. As your knowledge of physics is limited, dont forget for consistent results tyre pressures should be measured 'cold'. ie with tyres at ambient temperature. Driving raises their temperature and their pressure increases. So 27psi measured on warm tyres on a garage forecourt are likely to be less than 27 once the tyres are 'cold'.And this difference is variable depending on distance driven etc.

              Its a good idea to do them at home before driving but diy gauges are not always accurate. An accurate gauge is ideal of course, but I have had poundshop gauges that are accurate and expensive ones that were not. When I get a new gauge I always 'calibrate' it by taking the cold pressures at home.I then drive to a garage forecourt and measure the pressure again with the same gauge. It may be a couple of psi higher due to the warm tyre. I then compare the result with the garage gauge at the same temperature to judge how accurate my gauge is. If its say a couple of psi out but consistent it can still be usable if for instance I know it needs to read 29psi to achieve 27 psi. It also gives you some idea how much higher you may need to go when using forecourt airlines.

              Comment


              • #8
                Originally posted by Bugman View Post
                Hi. As your knowledge of physics is limited, dont forget for consistent results tyre pressures should be measured 'cold'. ie with tyres at ambient temperature. Driving raises their temperature and their pressure increases. So 27psi measured on warm tyres on a garage forecourt are likely to be less than 27 once the tyres are 'cold'.And this difference is variable depending on distance driven etc.

                Its a good idea to do them at home before driving but diy gauges are not always accurate. An accurate gauge is ideal of course, but I have had poundshop gauges that are accurate and expensive ones that were not. When I get a new gauge I always 'calibrate' it by taking the cold pressures at home.I then drive to a garage forecourt and measure the pressure again with the same gauge. It may be a couple of psi higher due to the warm tyre. I then compare the result with the garage gauge at the same temperature to judge how accurate my gauge is. If its say a couple of psi out but consistent it can still be usable if for instance I know it needs to read 29psi to achieve 27 psi. It also gives you some idea how much higher you may need to go when using forecourt airlines.

                Comment


                • #9
                  Forecourt gauges are not always 100% accurate either but should let you know if yours is in the right ball park.If they only differ by a psi or two it may be yours that is the more accurate so just stick with that. If its more than this check it against a couple of other air lines before blaming your gauge. As long as the car feels right a pound or two inaccuracy is less important than ensuring the pressure, whatever it may be, is equal on both tyres on the same axle.

                  Comment


                  • #10
                    Hi B.,
                    Sorry for delay in responding.

                    Thanks for ur views, didn't think t forecourt gauge would possibly be that inaccurate.

                    Thanks again,

                    Max.

                    Comment


                    • #11
                      Forecourt gauges are routinely checked but they get all sorts of abuse from people who drive over them, drop them, generally batter them - I know the place I used to work the gauge was rarely 100% accurate even a few days after we'd fitted a new one.
                      1972 Viva restoration thread - http://www.thecorsa.co.uk/projects-b....html#post1534

                      Comment


                      • #12
                        A little anecdote. I used to compete in off road motorsport. Tyre pressure was critical to grip and a minimum permissible pressure was set for each course. Often as low as 5 psi. I bought a very expensive 0-20 psi gauge . Useless for road use. I was halfway through my first season before I noticed at scrutineering that 5psi on my gauge was actually 6 psi on everyone elses,putting me at a disadvantage.

                        Comment


                        • #13
                          Hi B.,

                          Sorry for delay in responding.

                          Just shows that there is quite a bit of inaccuracy even with expensive pressure gauges.

                          Thanks for comments,

                          Max.

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