Digital Speedo Vs Dial

Our VW Polo has a digital speedometer which always reads 2km/hour less than the dial speedometer. It's not to do with reaction time as we can maintain the same speed and the reading on both is consistent.

Which one would you trust?

Comments

  • So as to avoid a fine, I'd go with whichever shows the higher reading (analog in this case).

    Download a GPS speedometer on your phone next time you're testing too.

    • Thanks, I didn't realise there was a GPS speedometer app, I'll download one and do a comparison :) And yes, we've been erring on the side of caution as you suggested until we figure this out.

  • +1

    Typically dials read over the actual speed by up to 10%. Most cars I have driven I have checked against GPS or in the good old days, those 5km speedo check lengths on the freeway. At 110 actual speed the dial is usually showing 115-120.

    2km isn’t much, trust the digital one because it shows you a more accurate speed quickly, rather than having to mentally count the strokes between the lines each time.

  • +1

    Neither…

    The ADR states that speedos must be set +0% to -10% I think, so at an actual speed of 100km/h, your display should be 100 to 110k's displayed. So there's a good chance neither are actually correct to your road speed.

    GPS readout is your best and easiest option for calibration; then you'll know which of your speedos is out and by how much.

  • Strange - in my car (Toyota 86) the analog dial and digital speedo show the same speed. I solely use the digital one since its quicker to read.

  • +1

    My "analogue" is +5% and I suspect that the digital reads off the same input as the "analogue". I'm sure they're both digital inputs.

    I'm also certain that the +5% is a setting as I have a separate readout for a bunch of random crap connected directly to the Canbus (car pluggy thingy). It reads closer to true.

  • Use a GPS speedo app. It will almost certainly show that your digital speedo is out by around 5-10% (the difference between analogue and digital is probably down to parallax error).

    In every state except for Victoria, the authorities do not care if you're doing up to 5km/h over the limit.

    • In every state except for Victoria

      Obviously never been to NSW.

      • Present me with a speed camera fine or a speeding fine for 5km/h over from NSW. A good number of people exceed the speed limit on freeways, the cops do not give a rat's about anything under 10 (except for school zones), and you can safely set your cruise on the Hume for 130 and not have any trouble from it.

  • I have experimented with the digital (between dials screen) speedo.
    I found it to take my eyes off the road more & for a split second longer.
    I think it has to do with the fact it takes a moment to update, so part of your brain waits for that split second it takes to update to confirm your speed.
    And even though it is a similar distance from taking your eyes off the road, I find I can see the analog Speedo in my peripheral vision and you can more easily just glance at the needle.

    The conventional analog speed just works, and maybe it is because we have been conditioned to it but I find it safer, more natural and easier (quicker) to read.

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