Separating Fact From Fiction: Evaluating Good and Bad Petrol-Saving Tips


As we approach spring again, driving season will soon be upon us and you may start to hear about petrol-saving tips. Some of the common advice you hear is good and will actually save you money. Other advice is untrue and probably not worth your time and effort. We’ll sort out the good and the bad here:


Bad Advice: Filling Your Tank in the Morning When It’s Cooler – The myth here is that since materials shrink at lower temperatures, that the petrol in storage tanks is more dense in the morning. This is really not worth paying any attention to. First of all, it takes a huge change in temperature to even move the volume of petrol by 1 percent. On top of that, the giant fuel storage containers at petrol stations are like giant insulators. There’s no way to know when to hit that perfect “sweet spot” where you might actually save 1 percent on your petrol. The bottom line is that if it’s convenient for you to get your petrol later in the day, go for it!


Bad Advice: Fuel Additives and Devices That Claim to Increase Your Mileage – There are a few items for sale that claim to increase your fuel efficiency, but they don’t really work. You’re probably best off just focusing on the things truly within your control below.


Good Advice: Check Your Tire Pressure – There is plenty of evidence to show that when your tires are under-inflated, your fuel efficiency suffers. Use your car’s owner’s manual and keep your tires inflated to the right pressure to get the best mileage related to tires.


Good Advice: Use Cruise Control – When you drive long distances, you’ll get better mileage by using the car’s cruise control rather than constantly speeding up and slowing down by using your foot on the accelerator. You may not feel like you’re doing that, but according to, it’s true. At a surprisingly high seven to 14 percent savings, this one’s important enough that you should really make an effort to select a car with the cruise control option if you’re buying, even if it means digging a little deeper into savings. While cruise comes standard on most new car models, if buying used, it could be a differentiating factor.


Good Advice: Shop Around for Petrol, Don’t Pay for Convenience – If you live near multiple petrol stations, don’t assume that one is always the cheapest. You can always do a check before you leave or on a smartphone for what the local petrol prices are. Remember, if petrol prices are too high and you’re short on cash between paydays but still need to get to work, you can apply for a payday loan to get the money you need to cover the cost of petrol.



Darwin is an engineer and MBA who takes an "evolutionary" approach to finance, writing about adapting to evolving financial management, tax, investing and savings opportunities. Making more money and saving more money is an adaptive process — join the evolution! He blogs at Darwin's Money and ETF Base

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