Speed showing incorrect on Tom Tom — TomTom Community

Speed showing incorrect on Tom Tom

CCobbCCobb Posts: 4 [New Seeker]
Where it shows the speed you are doing on the built in sat nav screen (next to the speed limit for the road), its showing my speed incorrectly , I know it is always different to your speedometer by a few MPH , this is why I always look at this for my accurate speed but it is suddenly showing incorrect by about 6 MPH which varys - is this a GPS Issue? Can it be fixed? Any help appreciated, thank you.

Answers

  • VikramKVikramK Posts: 10,559 Moderator
    edited November 5
    Hi @CCobb

    Welcome to the community!
    The current speed displayed on the device should ideally be much more accurate in order to calculate a GPS position from signals sent by satellites. Thus the speed shown on a GPS device is closer to the actual driven speed than what is displayed by the car's speedometer.

    When was the device last updated? Some helpful information on this article-
    https://help.tomtom.com/hc/en-us/articles/360013960459

    Regards, Vikram
  • YamFazManYamFazMan Posts: 17,984
    Superusers
    Hi
    @CCobb
    The speed differential displayed on the two devices will be a percentage difference....
    A much larger speed difference displayed on the Motorway than in a Town....

    Stay Safe... ATB YFM
  • CCobbCCobb Posts: 4 [New Seeker]
    Thank you for the advice, the speed difference did keep changing depending on the roads I was on yesterday as I go through a range of 30,40 and 70 roads, just for example, on the 30 roads , tom tom said I was doing 22 , speedometer said spot on 30, on the motorway tom tom said I was doing 66 speedometer said I was doing 73. They have always had a difference of about 2-3 which Is why I go off the tom tom as I think that is the most accurate. I put waze on my phone yesterday to see what that said, all 3 were different!
  • YamFazManYamFazMan Posts: 17,984
    Superusers
    edited November 5
    Hi
    @CCobb
    That's a big difference between the two readings have you fitted tyres with a different profile or bigger diameter wheels and low profile tyres... If 'Yes'... Did you choose a low profile tyre with the same Rolling-Radius as the original tyre or the Speedo will need recalibrating....

    See... Wikipedia 'Speedometer'
    See Here UK Rules... https://en.wikipedia.org/wiki/Speedometer

    Stay Safe... ATB YFM
  • CCobbCCobb Posts: 4 [New Seeker]
    I know, proper baffling and confusing me - no idea what speed I was actually doing! Not changed my tyres since January and its all been fine since, I had some work done on my gear box but that was a few months ago and its all been fine since then. Going to head out with someone in the car with me at the weekend so they can drive and I can watch the speed of everything at the same time and take it from there I think is probably my best approach - when tom tom was saying I was doing 22 and speedo was saying 30 It did feel like 30 I was driving at and not 22
  • NiallNiall Posts: 10,833
    Superuser
    edited November 5
    @CCobb

    Do you have a speed trap near you that displays the speed you are travelling? They are far more accurate than your actual speedometer. Normally your GPS and one of those displays are within couple of mph :)
  • CCobbCCobb Posts: 4 [New Seeker]
    Thats a Great Idea Niall, thank you
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