odometer calibration

[hecatti]

Hello!
I took my handheld gps in my truck to a little measures to be done , and found incorrect odometer readings.
the gps measured distance 56 miles but odometer showed only 46 miles... how can I make this accurate??
speedo shows correct speed according to my gps.
thanks!

[LB72004]

verify that the tune has the right tire size for your rig. if the speedo and odo dont match it may be that the needle is off. monitoring your speed with the scan tool and compairing it to your GPS will show you if it is or not. not all GPSs are spot on and can be off by a few miles. most wont account for changes in elevation in their calculations. ie: they think in 2D not 3D

[THEFERMANATOR]

What OS are you running? I know gassers have one setting for speedo, and another for odometer. Some 01 OS's may be this way as well. I'm running a 6006 OS and my odometer is SCARY accurate(off less than .5 mile over 100 miles of driving, verified by GPS and mile posts), my speedo on the other hand is only accurate at 70.

[hecatti]

Hello!
Thanks for response, my current OS is 02444105 , my tire size is set right, the odd thing is that speedo, scantool and gps indicates same speed exactly,
my friend have same kind of truck with same tire size , only difference of our speedo calibration is, he is running 6006 OS, every one of tunetools speedo calibration cells have same value and tcm values are same also.
within 100 mile trip my odo displays 9 miles too short , but my friends odo is accurate both measured with gps.

maybe only way to solve this is set speedo cal. way off , until odometer is accurate and set my scangauge speed- pid accurate with gps, remove gauge cluster film , remove the needle put jack stands under rear axle when tires are 2 inch above ground and you know the rest....