dyeguy1212

iTrader: (1)

Looking at a tuner to account for the 275/70's I want to run. For those that used a tuner (SCT preferably?), when you change tire size for the speedometer, has anyone confirmed it's also changing the MPG readout.


Reason for question: MPG calculation could be an entirely separate part of the software from the speedometer.

Kevinpmac

I have SCT Livewire and went through the recalibration after changing from 18" to 20" wheels/tires. I used the revs per mile data from Tire Rack website. My speedo is spot on and MPG calculation is as accurate as before.

I suspect the speedo/odometer is only one of the data points in calculating MPG. Make it accurate and your MPG reading will reflect accordingly.