[Mikes1992]

I'm a bit of a sceptic when it comes to weight reductions. Maybe reducing rotating mass would have a slight difference but in my opinion weight reduction only helps if you use your brakes allot. I remember driving home with 200kgs of compost in my boot, I decided to test a hypothesis that the extra weight could be used as an inertial battery in order to coast further and the car definitely did do this.... I usually get about 75mpg on my drive home.... That day with 200kgs of extra weight I got 80mpg. Granted it could've just been coincidental but I suspect driving style has allot more to do with the fuel savings by reducing weight. Sure it will increase rolling resistance slightly but the biggest difference is the amount of inertia your car will have at any given speed.