As mentioned in the EU tyre labeling guide, whilst an important part of the equation, tyres are not the only factor to consider when looking at fuel efficiency on a car. In particular the way in which you drive can have a dramatic impact on the MPG you get or how often you have to fill that tank. Simple tips include pulling away a little slower, not rushing to hit the speed limit but instead taking your time, which can lead to incredible savings. Tyre pressure: The Government estimates that low tyre pressure can increase rolling resistance by as much as 10% leading to signicantly lower MPG.