Leaving the tailgate down does not save gas. However, leaving the tailgate up does. This is done by the “separated bubble effect” which causes the drag to reduce. As a result, you get the maximum amount of MPGs out of your truck.
Does Leaving the Tailgate Down Save Gas? How?
This is a very common and debatable question among truck or pickup owners. Some will say it doesn’t make a difference whether the tailgate is up or down. The old-timers will swear that driving with the tailgate down increases gas mileage. The reason behind this kind of thinking is explained below.
How Does Leaving the Tailgate Down Save Gas?
Most people believe that leaving the tailgate down helps the weight displacement to ensure a smooth ride. They tend to think that running with the tailgate down decreases drag. They believe that a closed tailgate creates an invisible wall. The air hits that wall and increases drag.
When a truck is running with its tailgate down, common sense says that air will flow more efficiently. The air will flow more easily through the truck bed and with less wind resistance. As a result, the driver will experience lesser drag on his vehicle and the gas mileage will go up.
Therefore, it is often believed to be the sure-fire way to save money on gas. For a long time, this looked like a plausible theory to many. However, leaving the tailgate down does not save money or gas. The correct way to increase gas mileage is to drive with the tailgate up or closed.
Surprisingly enough, this is the truth most people are not familiar with. There is a science behind this argument. Upon the tailgate closed, this creates a particular type of airflow known as a separated bubble. This airflow resides within the confines of the truck bed.
This bubble of slow-moving air deflects the wind and carries it over the raised tailgate during motion. The surrounding air coupled with the deflected air creates a vortex effect. This vortex is the very reason the vehicle does not feel any additional drag.
As the pickup does not have that extra drag, it saves gas cost. With the gasoline cost going out of hand, this is a fact that all should be aware of. However, when a driver drives with the tailgate down, the “separated bubble effect” does not take place.
The air that is coming off the roof hits the truck bed. This causes to reject the positive wind effect. Additionally, it creates a downforce. The air is pulled towards the truck which causes more drag due to the downforce. In other words, the vehicle becomes effectively heavier. Therefore, you will experience no increase in MPG.
Moreover, driving with the tailgate down makes the driver feel vulnerable. The hinges become weak and shaky. It is also a pretty unsafe way of driving. As people are becoming more aware than before, they hardly drive with the tailgates down these days. If you want to experiment, we suggest you take the tailgate off completely.
Therefore, it is clear that driving with the tailgate up or closed is the more fuel-efficient way of driving. The commonly known myth is no longer the truth. Keeping the tailgate up is the best way to get the maximum MPG out of your pickup.
Frequently Asked Questions
Q: Will it be illegal or dangerous if I drive without a tailgate?
Ans: Driving without a tailgate is not illegal but it could be dangerous. This is because the underneath airflow and the trailer can drag the truck underneath the trailer. Besides, if the truck is loaded, driving without a tailgate could be disastrous.
Q: Does a vented tailgate increase gas mileage?
Ans: You will see no noticeable difference in gas mileage with a vented tailgate. However, this kind of tailgates does have its benefits.
Q. Does tonneau cover improve MPG?
Ans: Yes, tonneau cover can improve MPG but only a little bit.
The argument about whether driving with the tailgate down increases gas mileage or not is a popular one. The majority used to believe, and still believe that it does increase fuel efficiency. However, science says otherwise. People these days are becoming aware of the fact and rejecting this popular myth. Leaving the tailgate down does not increase gas mileage, leaving the tailgate up does.