456 Speedometer calibration | FerrariChat

456 Speedometer calibration

Discussion in '456/550/575' started by Doug R, Dec 18, 2023.

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  1. Doug R

    Doug R Karting

    Oct 11, 2005
    208
    Yellow Springs Ohio
    Hello All,
    While my odometer is very accurate my speedometer is off by about 10%. Doing the corrective math in my head while driving is not too difficult but is annoying nevertheless. Is there a cure?
     
  2. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    13,974
    MO
    Full Name:
    Omar
    What is your wheel size.
     
  3. Doug R

    Doug R Karting

    Oct 11, 2005
    208
    Yellow Springs Ohio
    Wheels and tires are stock.
     
  4. Doug R

    Doug R Karting

    Oct 11, 2005
    208
    Yellow Springs Ohio
    Front 255/45/17
    Rear 285/40/17
    Pretty sure that’s stock but the rims definitely are
     
  5. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    13,974
    MO
    Full Name:
    Omar
    Then Speedo calibration. They tend to read 5% fast but 10% seems oddly high
     
  6. Doug R

    Doug R Karting

    Oct 11, 2005
    208
    Yellow Springs Ohio
    How do you calibrate these?
     
  7. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    13,974
    MO
    Full Name:
    Omar
    Any cluster repair shop; there is a famous in the LA area from memory. My 328 had odd ball issues like this though the speedo in that car would be all jittery.
     
  8. 308 GTB

    308 GTB F1 World Champ
    Rossa Subscribed

    Feb 7, 2002
    11,722
    New Jersey
    Full Name:
    Barry Wolinsky
  9. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    13,974
    MO
    Full Name:
    Omar
    #9 Auraraptor, Dec 19, 2023
    Last edited: Dec 19, 2023
    Yup that was them !

    Before you send it though, triple check the issue is localized entirely to the speedometer; if your car is 97+, check the speed via obd2
     
  10. Doug R

    Doug R Karting

    Oct 11, 2005
    208
    Yellow Springs Ohio
    It’s a 95. I appreciate all the input I was hoping maybe somebody had been there done that themselves. Not sure it’s worth the effort to pull it though.
     
  11. mominayal

    mominayal Karting

    Feb 2, 2017
    119
    Indiana
    i have a 95 thats also about 10% fast. In reading through other threads its seems like about the norm with a range of 5-10%. Advice on those threads also steer against trying to fix it as its seems more trouble than its worth.
     
  12. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    39,174
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    Especially since the odometers seem to be pretty accurate.
     
  13. Doug R

    Doug R Karting

    Oct 11, 2005
    208
    Yellow Springs Ohio
    Yea it is odd that the odometer is spot on.
     
  14. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    13,974
    MO
    Full Name:
    Omar

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