How to Correct Speedometer for Tire size / Axle Ratio
Click button under picture for detailed instructions.
Confirm nGauge has firmware 262 or higher. Firmware is listed at the bottom of the splash screen when booting up.
Click Here for How to Update nGauge Firmware
Click Here to Download the latest Firmware (FW-290)
At the main menu, select Tuning then Module Config. Follow the prompts to reach the tire size adjustment screen.
Using "+" and "-", adjust tire size. To change to axle ratio, press the Right Arrow. Press the Check Mark when set.
With size/ratio updated, turn off ignition for 15 Seconds and press the Check Mark to finish.