it's debatable whether either is correct. I'm not too concerned about the weight (correctly, mass) of a full tank really impinges upon your fuel usage.
I think driving style makes far more difference to your MPG figures.
Anyway, fuel MPG is not the biggest cost of car ownership and usage. Simply owning the things costs you money with depreciation, servicing, consumables (tyres, lamps, pads and discs etc.).
I have a mate who drives around in a 4.4 litre BMW 540i estate. Yes, 19mpg is not impressive. But he only covers 4000 miles per year, so what's the big deal?
And in a car that weighs in at nearly two tons a few extra gallons of petrol (lighter than diesel) it really makes no difference to the already poor economy.
Furthermore, hwo much difference does a full tank make to your fuel usage when you're driving in first gear most of the time? |