Corrected MPG
Adjusts trip-computer MPG for the odometer error a taller tire introduces.
MPG impact
Enter your indicated MPG and tire sizes to get the corrected figure, plus an annual fuel-cost estimate.
What it does
Adjusts trip-computer MPG for the odometer error a taller tire introduces.
Estimates yearly fuel spend and the difference between two fuel-economy figures.
Separates the measurement correction from the real 1 to 3 mpg loss bigger tires usually cause.
Usually yes by 1 to 3 mpg from added weight and rolling resistance, but the trip computer also under-reports MPG because the odometer under-counts miles. This tool separates the two.
A taller tire travels farther per revolution, so the odometer counts fewer miles than you actually drove. That makes calculated MPG read low until you correct for the diameter change.
Sometimes. On big tires a regear can put the engine back in its efficient range and recover part of the lost fuel economy, though it does not undo the added weight.