Seymour said the car in front of him was driving erratically, speeding up and slowing down in the right lane.

  • Ilovethebomb@lemmy.nz
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    8 days ago

    I’ve seen almost 10% out, checked against a GPS app on my phone, so almost 110 on the speedo to travel at 100 actual.

    I’ve actually fitted tyres a size bigger than recommended to get a speedo to read accurately.

    • Dave@lemmy.nzM
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      8 days ago

      I’m not sure what standard this refers to, but I dug up this article I remember reading previously (it doesn’t appear to be published on the site anymore)

      The applicable standard for many vehicles sold in NZ is a European standard that specifies that speedometers must not indicate a speed less than the vehicle’s true speed, or a speed greater than the vehicle’s true speed by an amount of more than 10 percent plus 4 km/h.

      If true, that means a speedo is considered legally accurate if it says 114 when you’re driving 100, which is a pretty massive difference.

      Bigger tyres is a nice workaround, both our cars over read by 4kph so I just do the maths.

      • Ilovethebomb@lemmy.nz
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        6 days ago

        A speedometer that far out is effectively useless, and if I bought a vehicle like that I’d take it up with the dealer.

        So yes, Seymour might not have even been speeding.

        • absGeekNZ@lemmy.nz
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          6 days ago

          This is one of my pet peeves; this is not the 1950’s; we can make speedometers accurate to within 3%…this margin would account for all the vagaries of tire pressure etc.

          Our newest car; pleasantly has a very accurate speedo…

          • Ilovethebomb@lemmy.nz
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            6 days ago

            Modern vehicles have GPS calibrated speedometers, and are often dead on. But for an electronic speedo, there’s no excuse for more than a few percent.