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Fill ‘er up! – Dispelling some gas myths

Every hobby, avocation and profession has ideological blind spots. Some of these beliefs are so profoundly rooted in its culture that they are accepted as fact and rarely debated. Such is the case with several questionable myths about gasoline and refueling. I did some research and compiled a list of some commonly held misconceptions.

Myth #1 – Newer Gas Stations Have More Accurate Pumps
Every state has a weights and measurements department responsible for regulating the proper measurement (volume) and quality of gasoline. Field officers regularly examine fuel dispensers and place a dated seal on the dispensers if they pass an inspection and meet all other legal requirements. If a dispenser does not pass the test, the department will decertify the dispenser and take it out of service until it is repaired, recalibrated and reinspected. Therefore, the age of the pump should not make a difference in its accuracy.

Myth #2 – Refuel in the Morning When Gasoline is Densest
Science defines the density of a substance as its mass per unit volume. While it’s true the density of a liquid will increase when temperatures drop, this factor isn’t relevant because of where gasoline is stored. With a few notable exceptions—notably in Alaska and northern Canada—virtually all gas stations dispense fuel from underground storage tanks where the temperature is constant. Because the temperature of the earth surrounding the tank doesn’t significantly change during the day, neither will the fuel’s density.

Myth #3 – Avoid Filling Up When a Tanker is On Site
There was a time when older stations using neglected equipment and inadequate filtration systems made this precaution advisable. Beginning in the mid-1980s, however, the EPA implemented uniform dispensing standards for all gas stations. For instance, gasoline is first filtered at the refinery and then filtered again before it’s pumped into a tanker truck. Whatever sediment might be stirred up at a station’s underground storage tank is minimal and will be captured by the dispenser pump filter before going into your bike’s gas tank.

Myth #4 – Only Buy from Top-Tier Gas Stations
One prevailing internet theory holds that name-brand gas stations like Chevron, Exxon, BP, Shell or Mobil provide a higher quality gas which yields better fuel economy. Since companies are required by law to add detergent additives, getting gas from a no-name gas station doesn’t mean you’re getting low-quality gas. Apart from a brand’s proprietary additives, they aren’t that much different. Therefore, you can choose whatever gas station is cheapest or most convenient. Nevertheless, I’d recommend avoiding gas stations that look like something out of a Mad Max movie. The risk of getting “bad” or “dirty” gas is likely to be higher at these places.

Myth #5 – Using a Higher Octane Will Improve Fuel Economy
Typically, most gas stations offer at least three octane grades: 87 (regular), 89 (midgrade) and 91 or 93 (premium). Fuel graded by octane is a measure of how much compression it can withstand before igniting, commonly thought of as its ability to avoid knock. Therefore, “premium” doesn’t necessarily mean the gas is better; it just means it has a higher octane rating. It is generally accepted that using a higher grade of gas than recommended doesn’t offer any extra benefits in terms of engine life, fuel economy or emissions. In short, follow the recommendation in your owner’s manual.

Myth #6 – Additives Increase Fuel Economy
To the extent that you want to keep your engine performing as designed, this suggestion has some merit. Normal wear and tear, high temperatures, and poor-quality gasoline can contribute to a buildup of deposits on the fuel injectors or in the jets of a carburetor and that can affect fuel economy. Using a reputable fuel injector cleaner like Chevron’s Techron or BG’s 44K at least once a year reportedly reduces these deposits and helps improve the efficiency of your engine.  However, there is no evidence that gas additives that promise exceptional performance and fuel economy—euphemistically referred to as “snake oils”—actually work.