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Speed Accuracy

Discussion in 'Motors' started by Captain Kirk, 24 May 2006.

  1. Captain Kirk

    Hitman

    Joined: 25 Aug 2005

    Posts: 717

    Location: Derbyshire

    I was having a "debate" with a friend the other night (whilst drunk) on speedo accuracy. I said it was crap, due to so many different factors (i.e. tread depth, tyre pressure, sensor accuracy etc) and that TOMTOM on my pda was a lot more accurate due to the gps. Could someone settle this argument or add any other comments on which one is more accurate. Cheers
     
  2. Acolyte

    Mobster

    Joined: 18 Oct 2002

    Posts: 3,768

    Location: Bristol

    GPS is far more accurate compared to your speedo.
     
  3. Glaucus

    Man of Honour

    Joined: 11 Mar 2004

    Posts: 76,645

    debate closed.
     
  4. MrMatteh

    Wise Guy

    Joined: 22 Feb 2004

    Posts: 2,418

    Location: Essex

    how could tomtom be *less* accurate is what you need to ask your mate
     
  5. Psycrow

    Mobster

    Joined: 16 Jan 2003

    Posts: 4,948

    Location: Kirkcaldy, Scotland

    GPS is accurate to something like 0.1m/s with a 3 or more satellite lock. Your speedo can be up to 10% out due to the many many little errors that mount up as you go through the system.
     
  6. Nozzer

    Banned

    Joined: 17 Oct 2002

    Posts: 9,495

    Location: Sunny South-East

    Unless you're going up/down hill. But it's still more accurate at a cruise.
     
  7. NathanE

    Capodecina

    Joined: 21 Oct 2002

    Posts: 18,022

    Location: London & Singapore

    How comes? GPS can determine altitude too ya' know? ;)
     
  8. Nozzer

    Banned

    Joined: 17 Oct 2002

    Posts: 9,495

    Location: Sunny South-East

    Simple trigonometry, my dear boy.
     
  9. Captain Kirk

    Hitman

    Joined: 25 Aug 2005

    Posts: 717

    Location: Derbyshire

    Thank you, I knew I was right. I don't like being wrong, and I'm not very often :D
     
  10. The_Dark_Side

    Capodecina

    Joined: 21 Oct 2003

    Posts: 13,608

    Location: Back with a Vengeance.

    so when you're at warp 9 does you're speedo read slow or fast?
    ;)
     
  11. PMKeates

    Capodecina

    Joined: 16 Jul 2004

    Posts: 14,043

    Mine just says 120mph, so definitely slow :confused: :D
     
  12. Captain Kirk

    Hitman

    Joined: 25 Aug 2005

    Posts: 717

    Location: Derbyshire

    At about 70, it reads around 65, so need to do about 75 according to speedo to be doing a real 70. In theory
     
  13. Dr Who

    Sgarrista

    Joined: 11 Nov 2004

    Posts: 8,145

    Location: Wiltshire

    Speedo accuracy varies at the speed you are travelling at...

    My accord was about 5mph over at 50 mph, at 100mph it was 1mph different to the tom tom gps!!!

    :eek:
     
  14. daz

    Capodecina

    Joined: 18 Oct 2002

    Posts: 24,003

    Location: Bucks

    I think you mean at 65, it reads 70. T'other way around. :o :p
     
  15. Lashout_UK

    Capodecina

    Joined: 2 Mar 2004

    Posts: 11,829

    Location: SE England

    Speedo in the 1850 was spot on.

    Speedo in the 1500....doesn't work, Officer :p