Whenever you see a semi-truck on the highway, have you ever wondered how much fuel the big rig holds or how far can it travel on full tanks of fuel?
Those are common questions, and unless you have driven a semi-truck, you may not know the answer.
I spent a few years driving a semi-truck around North America and was always impressed by how far these trucks can actually go on full tanks.
So in this article, I will show you the average range of a semi-truck with full tanks along with some other interesting information.
What is the range of a semi-truck?
The size of fuel tanks on a semi-truck can vary, but on average, the standard tank can hold between 110 to 150 gallons.
125-gallon tanks are quite common although it is possible to get trucks with larger tanks of up to 300 gallons.
There are 2 fuel tanks on a semi-truck so the total amount of fuel can be up to 250 gallons.
Semi-trucks will burn about 6 miles per gallon (MPG) on a flat surface and this number can drastically change based on various factors.
By the numbers, two standard tanks with 125 gallons of fuel can theoretically carry a semi-truck with optimum mileage of nearly 1,500 miles.
With larger tank sizes, the range will increase. If a semi-truck has 150-gallon tanks or 300 gallons total, the range will increase to around 2000 miles.
However, there are many factors that will impact that mileage.
The range of a semi-truck is directly affected by its weight. The heavier the truck is:
- The higher the fuel burn
- The lower the range
The weight of a semi-truck includes the weight of the:
Most big rigs use a diesel engine for higher efficiency and increased torque. Diesel is a slower-burning fuel that can generate more power per cylinder explosion and generate more force on the gears within the transmission.
While a passenger vehicle with a diesel engine may produce a lot of chatter and noise, in a large, bulky vehicle like a semi-truck, the chatter isn’t felt by the driver.
Curiously, a semi-truck hauling an empty trailer gets about the same mileage as a semi-truck hauling nothing.
Additionally, a semi-truck hauling nothing is a dead loss of fuel and maintenance to the company; even hauling an empty trailer, there is some payout.
The weight of diesel fuel is also a serious consideration. As noted above, the standard tank that comes with a semi-truck is 125 gallons. Diesel fuel weighs around 7 pounds per gallon.
Fully loaded, that additional 1750 pounds will eat into the mileage of a semi-truck.
The terrain that a diesel truck has to cover has a strong impact on the amount of fuel used.
For drivers who need to climb rugged mountain highways, mileage can drop to just about 2 MPG, while the downhill run can break 20 MPG.
A long, slow climb can actually pull quite a lot of fuel before the driver reaches the next downhill.
If you are ever on a hilly road or a steep grade with many diesel trucks, stay flexible. They will be slow on the climb but may pass you on the way down.
Because these trucks are so heavy, drivers often need to use the power of the engine to slow the vehicle.
Semi-trucks produce a lot of wind resistance. When winds are high, some highways forbid the transport of empty trailers, and during strong winter storms, there are many states that will just close the highway entirely to semi-trucks because of the risk of a wind-driven tip.
There are some drivers who will try to “draft” or allow the speed of their car to be controlled by the air vacuum created at the back of a big rig driving at highway speeds. This action actually doesn’t work.
The semi-truck is larger than your vehicle, but it’s also taller. There may be a bit of a vacuum directly behind the trailer, but where your car is there is actually a sort of windstorm coming from below the truck.
Additionally, if the big rig needs to stop suddenly or tosses up a piece of debris, you could be killed. Pay for the gas.
It’s often recommended that a driver should take a break and fuel up every 300 miles. For those with larger tanks who can break the recommended 300 miles, the range of many big rigs can actually be quite astonishing.
However, there are limits on the hours that a driver can be on the road without facing penalties.
Additionally, unless a driver is trying to beat a storm or a cold front, such a driving choice could be dangerous.
The force of the wind can really limit mileage. For drivers who need to cross the central and southern plains of the United States, a steady summer wind of 20 mph through Nebraska, Kansas, Oklahoma, and Northern Texas is not uncommon.
The buffeting from gusts can steal a driver’s focus and the steady push of hot air will cut into their mileage.
As mentioned, it’s recommended and certain schools encourage drivers to plan a fuel up every 300 miles. Although I have driven way past that distance without stopping for fuel.
Drivers should consider taking a break, stretch and get a meal by that point. The longest shift a driver can take on is 11 hours; at that point, they will need to stop and take a 10-hour break.
What About Gasoline and Natural Gas?
While gasoline is cheaper at the pump than diesel, a semi-truck with a gasoline-powered engine will actually be less efficient on the road.
Gasoline just burns hotter; it puts more pressure on the engine and provides less power per “pop” or burst of fuel at the cylinder.
Natural gas vehicles are much cheaper to fuel up; compressed natural gas, as of November 2022, is about 1/3 of the price of diesel fuel.
However, a truck that will run on CNG is much more expensive than one that will run on diesel. Additionally, fuel station access is limited.
While CNG vehicles are quite safe and powerful, they’re not terribly popular with semi-truck designers and manufacturers.
Finally, the cost is a big consideration when pricing out shipping via semi-truck. As of November 2022, the average price of diesel per gallon in the United States was $3.82.
In many regions, it is much costlier. Unlike gasoline prices, which tend to bounce around a bit, the price of diesel only seems to go up and stay there.
If a semi-truck had two 150 gallon tanks at the average cost of diesel, it would cost $1,146 to fill up.
Additives Can Drive Up the Cost
Diesel is not a fuel that tolerates cold weather well. In extreme cold and with no additives to increase liquidity, diesel fuel can gel up and clog filters and hoses, leaving the driver stranded.
These stabilizing and anti-gel additives need to be added on a per-gallon basis. Drivers headed into cold country will need to include these additives in their fuel estimates.