Question & answer
Do Running Boards Hurt Gas Mileage? What Is Measured and What Is Only Claimed
Nobody we can find has published a measured mpg figure for running boards, so anyone quoting a number is guessing. The written claims even point in opposite directions: GM's aerodynamics team said some boards can help airflow, and a Toyota patent says fixed boards hurt it. Do not pick or skip boards over mileage.
The straight answer
We found no published mpg test, so nobody can honestly give you a number. GM's aerodynamics team said in 2013 that tube and flush-mounted boards can help airflow. A Toyota patent says fixed boards tend to disrupt it. The makers we read print no mileage figure. Treat mileage as unknown and choose boards for getting in and out.
Sellers and forum threads will tell you boards cost you mileage, or that they somehow help. Straight answer: we looked for a measurement and did not find one. Here is everything we did find, and how much weight each piece can carry.
Who says what
| Source | What it says | Measured figure? |
|---|---|---|
| GM aerodynamics team, reported by Work Truck, 2013 | Round tube boards "can help smooth out airflow" along the side of a pickup; flush-mounted boards are better | None |
| Toyota patent 10081302 | A fixed board "tends to disrupt airflow", with increased drag and decreased fuel efficiency | None |
| Toyota patent 10081302 | A retractable board "may do little to improve vehicle aerodynamics" | None |
| Decoma patent 6375207 | A retracted board "can also improve the aerodynamics of a vehicle" | None |
| Installation sheets we read for AMP, Tyger and Rough Country | Nothing about mileage | None |
So the sources disagree, and every one of them is talking without a number. The one coming from an engineering team that studies this for a living favors boards, yet it is a 13-year-old trade report about GM's findings, not a test you can read. A patent background sets up a problem for the invention to solve, so read it as a claim and not a result. Neither kind of document tells you what will happen on your truck.
What the government numbers do and do not tell you
The Department of Energy's fueleconomy.gov page says extra weight lowers mileage and that cargo on the roof adds drag. Its drag figures cover cargo boxes and trays and its weight figure covers anything you carry. None of them is about a step along the cab. We are not going to multiply those numbers by the weight of a pair of boards and hand you the answer as if it were a fact, because board weight varies by part and the airflow side is the open question.
What you can say from it is modest. Boards add some weight, and they change the air along the side of the truck in some way. How far that moves your mpg is unmeasured in anything we read.
How to treat this when you are shopping
- Do not pay extra for a mileage claim. A title or sales page promising better mpg needs to show its test. We have seen none.
- Do not skip boards over it. If climbing into your truck is the problem, solve the problem. Whether boards are worth it is about access, looks and cost, and that is what are running boards worth it? goes through.
- Do not buy a power step for fuel savings. Buy power running boards if you want the step tucked away. The two patents above disagree on the aero, and the guides we read for those parts promise nothing about mileage.
- Think about clearance separately. A board that hangs lower is a different question from one that costs mileage. See do running boards reduce ground clearance?.
If mileage is off the table as a deciding factor, the next question is fit. Start with side steps for the common styles, or go to running boards by truck for your year and cab. The home page has the truck picker, and how we verify fitment explains why we only quote what a source says and print no number when there is none.
Tailgate questions
How much mpg do running boards cost you?
We cannot give you a figure, because we found no published measurement for running boards on a pickup. The claims we found are only descriptions of airflow, with no numbers attached. Any specific mpg loss or gain you see quoted needs a source, and we have not found one.
Do power running boards save gas because they tuck away?
It is claimed, and it is disputed. A Decoma patent says a retracted board can improve aerodynamics and fuel efficiency. A Toyota patent says a retractable board may do little for either. Neither gives a measured value, and patents are not road tests, so do not buy a power step expecting to get its cost back at the pump.
Do nerf bars or flat boards do better on mileage?
GM's aerodynamics team, as reported in 2013, said round tube boards can help smooth airflow along the side of a pickup and that flush-mounted boards are better. That report gives no measured numbers, and it covers GM's findings and not every aftermarket board. It is a hint at most, not a reason to choose one style.
Where this comes from
Keep reading
- Question & answerAre Running Boards Worth It on a Truck? Benefits, Downsides and Who Can Skip ThemAre running boards worth it on a truck? Yes if the climb is a daily chore. The real downsides, install work and warranty lines, and who can skip them.
- Question & answerDo Running Boards Reduce Ground Clearance? Fixed, Drop and Power ComparedFixed boards cut the room under the side of the truck, not the spec-sheet figure. How fixed, drop and power steps differ, and how to measure your own truck.
- Buying guidePower running boardsPower running boards come out with the door and fold away after. See which trucks each listing names, what the install takes and which load figures hold up.
- Buying guideSide stepsTruck side steps come as rails, 6-inch boards, drop steps and power steps. Compare styles by year and cab, with fit marked as the listing or maker states it.
- About usHow we verify fitFit here is what a listing title or maker sheet states, marked as such. What we read, what blocked us and why you still confirm year and cab before you buy.
Who writes this
runningboardsfortrucks.com Editorial Team
Fitment, buying advice and explainers
We are the editorial team at runningboardsfortrucks.com. We read listing titles, maker pages and instruction sheets, then write down which truck, year and cab each one states and where we read it. We do not run lab tests and we do not own a test fleet, and we say so openly.
- Fit quoted from the listing or maker
- Sources and dates on every page
- No lab tests, stated openly
- Publisher details in the imprint