I was able to adjust the tire size on my co-workers' '06 Silverado by following the EFILive tutorial. It corrected the speedo and the odometer, and eliminated the ABS light. I went to "Speedometer", clicked on "Parameters" and entered the values. It worked.
Now I need to adjust my '06 LBZ 2500HD for the new 285/75/16 tires I'm running. When I go to "Speedometer" and "Parameters" the table that asks you for tire dimensions doesn't pop up. There are just 4 parameters displayed on the right, starting with "Tire Revolutions per Kilometer". Can someone point me in the right direction? Thanks.