If you aren't running the factory tire size on your car, truck or motorbike not only does your speedometer go out of whack but your odometer will too!

The problem I found was I was using my odometer to calculate my fuel economy, and little did I know my odometer was 3.8% off! To fix this I made an equation which calculates the percentage difference between the old and new tires and then uses this to calculate the actual fuel economy! Now instead of getting out the calculator at the servo every time why not simplify the process by letting an app do the work.

1. Enter your cars factory tire size
2. Enter your new tires size
3. Enter the km's driven
4. Enter how many litres of fuel you used
5. FOLLOW @truebluetouring on instagram

The last one is optional but seriously though worth a follow :)

*Note the app works on the metric system - Imperial system coming soon!
** If you have put a spedo corrector on your car then the odometer will be corrected too and theres no need for this app