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Thread: HOw do you correct the speedo on a 2001 Silverado

  1. #1
    Advanced Tuner
    Join Date
    May 2007
    Posts
    489

    HOw do you correct the speedo on a 2001 Silverado

    I went from the stock 265/75/16 to 285/70/17 and now at 60mph I am really doing 62mph.

    It has not triggered any lights, but it is adding miles to the odometer and is throwing my mpg calculations off as well.

    Has anyone using the new 2.23 been able to recalibrate their speedo with this tire size yet?

  2. #2
    Tuner
    Join Date
    Dec 2008
    Location
    Houston, Texas
    Posts
    129
    2.23 here, use the calculator in the editor to find your tire height and put that in to your speedo>gear/tire calc table, if you have stock gear ratio put stock gear ratio and new tire height

  3. #3
    Advanced Tuner
    Join Date
    May 2007
    Posts
    489
    Ok so now here the funny thing.

    Stock tires were 265/75/17 which is 31.65" tall, HPT shows the stock calibration has 30.62 (confusing). Now my new tires are 285/70/17 (32.71") if I put that into the calbration the speedo is way off.

    So how does GM calibrate the tire height?

  4. #4
    Senior Tuner
    Join Date
    Dec 2009
    Posts
    1,084
    Not sure but maybe just try the adding difference to what Hpt showed as stock?

    31.68

  5. #5
    Sometimes they use the actual measured height of the tire.

    AKA when loaded and on the vehicle a 31.65" tire may measure 30.62.

    Grab your tape measure and check it out