Smiles per Gallon

The matter of fuel economy is often something that people over focus on when coming to a decision on a car purchase; I mean admittedly there are plenty of people who choose a car on looks, brand or even colour, but for anyone putting an ounce of thought into the facts and figures, mpg is probably one of the first numbers their eyes will look for. However how much difference these often irrelevant numbers will make to total costs associated with a car is often not as large as manufacturers and the government would have you believe.

I admit I am one of these people who probably pays a little too much attention to official mpg figures as opposed to other costs associated with a car. My personal acceptable mpg figure is 30mpg, and anything too much below that instantly turns my stomach regardless of how things like potential depreciation, road tax and servicing might stack up in favour of the vehicle in question. I have no real reason why I’ve chosen 30mpg as my requirement…I guess because at the moment I do relatively few miles it does not necessitate the need for a hypermiler, and also a big factor is probably the fact that the type of cars I’m looking at (ie large SUV’s) tend to average around that figure, on a good day perhaps. My current fuel consumption figures no doubt play a big part too but more on that later.

To be fair I have previously had this moment of enlightenment when it came to nearly choosing the Porsche Cayenne S as my ride, but even though I knew it made financial sense for me to choose a car that only cost £8000 to buy, £280 p/a in tax and only needed servicing once every 15-18k miles, the fact that it would have probably returned under 20mpg made me jumpy enough to change my mind pretty easily (although the rude dealer didn’t help matters!). Immediately I abandoned the idea of a cheap gas-guzzler and switched my mind to vastly more expensive and potentially less reliable diesel rivals.

Even now though I get a little nervous over the drop of 1-2mpg in the official figures, knowing that this likely translates to 3-4mpg less in real terms. To try and get my head around this (and make things a little less confusing for you readers) I’m going to list the different potential running costs of each of my options…although it’s only fair that I forgo servicing costs and any potential reliability issues as these will be variable for each example not just the model!

*Figures are based on diesel prices of 133.9p/litre and covering 7000 miles p/a.

Audi Q7 3.0 TDI S Line: 27mpg (official)-£1352 / 25mpg (realistic)-£1460. Tax-£490

BMW X3 3.0sd M Sport: 32mpg (official)-£1141 30mpg (realistic)-£1217. Tax-£280

BMW X5 3.0d Sport: 31mpg (official)-£1178 / 29mpg (realistic)-£1259. Tax-£280

BMW X5 30d SE: 34mpg (official)-£1074 / 27 mpg (realistic)-£1352. Tax-£280

Land Rover Range Rover Sport 2.7 TDV6 HSE: 28mpg (official)-£1304 / 27mpg (realistic)-£1352. Tax-£490

Land Rover Range Rover 3.6 TDV8 Vogue: 25mpg (official)-£1460 / 25mpg (realistic)-£1460. Tax-£490

Mercedes ML320 Sport: 30mpg (official)-£1217 / 28mpg (realistic)-£1304. Tax-£475

Volkswagen Touareg 3.0 TDI SE: 28mpg (official)-£1304 / 25mpg (realistic)-£1460. Tax-£475

Volvo XC90 2.4 D5 SE: 34mpg (official)-£1074 / 32mpg (realistic)-£1141. Tax-£280


As you can see the difference between fuelling a car like a Range Rover vs something relatively fuel efficient such as a BMW X3 does not cost all that much more…only £250 or so, a difference closely mirrored in road tax figures. Some of these cars cannot be bought without the higher rate of tax, which came into force from March 2006, so if the car isn’t available on a 55 plate or older they have to rely on having low emissions (below 225g/km) to get the cheaper tax. Some cars (like the BMW X5) reduced their emissions shortly after these regulations were put into force, but it means pre 2008 cars tend to be stuck with the higher rate tax.

Another important cost factor that can go unnoticed is insurance pricing; you’d assume that as all of these vehicles weigh above 2 tonnes and are powered by large diesel engines that insurance for a 23 year old would be expensive…and you’d be right, but some vehicles are surprisingly less than others. I can’t be bothered to go and get a load of quotes right at this moment but the results vary significantly based on ones I have gotten in the last few months. The cheapest to insure (circa £600) are the two Range Rovers (Sport and TDV8), followed by the Q7 and XC90 (around £700), Touareg  and X3(£750), with the most expensive being the X5 and ML at around £800 per year. It is rather surprising that a large poweful car such as the Range Rover, or one with a footballer-esque image, the Sport, are by far the cheapest to insure, but it does bear considering against other costs.

somehow this would probably have cheaper insurance than a Volvo?!

I guess I have sort of gone off topic now, but I just wanted to demonstrate that just because a BMW X5 is supposed to get 34mpg, in real life it’s only really going to cost a few hundred more to run a full fat Range Rover…providing that my mileage stays low and it remains reliable (both dubious statements). Going back to my current car and you may be quite surprised to know that it averages a pretty steady 30mpg in my day-to-day driving, which pretty much matches it’s official figures (though those are for when it runs on LPG presumably). My most recent half tank returned 29mpg, and although petrol is indeed cheaper than diesel the difference over a year is still likely to only about £50 compared to a diesel car returning similar mpg. Admittedly parts and servicing are likely to be pricier, but the latter already costs me about £350 a year and has to be done annually, as opposed to variably like these cars. Tax at £190 p/a is admittedly less than all them, but only £80 less than some.

On a final point, the tank before this 29mpg one returned a much more palatable 34mpg, but that included a 250-mile motorway jaunt and the use of 99 octane fuel (only 1p less per litre than diesel). Type of driving accounts for the majority of this difference I’m sure, but also the fact the car was ragged a little bit last week just goes to show that having fun in your car doesn’t really dent your wallet too much 🙂


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