Fuel weighs less than 1 kilo per litre
(Gasoline weighs about 6.1 pounds per gallon (lb./gal.) (728 g/L).)

so a full tank at 55 litres weighs 40.04kg
this is only 3.1% of the total weight of the car


in a car weighing 1285 kg is the extra going to make that much difference?

This may be of interest if you want to save fuel
http://www.save-petrol.co.uk

FYI your £25 pounds worth will be about 22L @ £1.10/L and will weigh about 16KG, assuming your tank is dry when you buy you are saving 33L or 24kg approx.

Its interesting reading this, as fuel consumption is the biggest drawback to owning a car, unless its a G-Wizz!

I tend to put 30L in at a time and aim to get 250-300 miles from each visit, I dont like to fill the tank as i cant help but feel i'm carrying extra weight unnecessarily, however you do need to fill the tank in order to get a true representation of your cars thirst :)