So. I am running 33in tires. When i out that into the calculator and go drove around my speed is reading fast by 5mph. To get my speedo within 1mph to gps i have tell the computer in running 31in tires wth is going on? I can post my tune file when i get home from work.
2011 Sierra 5.3l,
Dart 427 with a Big cam, Big intake manifold, Big injectors and a Big ass Turbo
I have run into the same issue a few times. If I remember correctly the tires on my Tahoe are about an inch and a half taller than the final figure that got me an accurate speedo. I figured it had to do with the loaded radius of the tire....but it really does not matter. One way or another I ended up adjusting a bit more and a bit more until the speedo was very accurate.
The tire and gear settings wont do it for you. All you have to do is change the pulses per mile either up or down.
ok cool. Thanks. Just thought something was going screwy.
2011 Sierra 5.3l,
Dart 427 with a Big cam, Big intake manifold, Big injectors and a Big ass Turbo
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