What Are Nerf Bars? Definition and How They Mount on a Truck

A running board is a step mounted below a truck's doors that makes it easier to climb in and out. A nerf bar is one form of it, usually a tube rather than a flat plank. That covers the short answer. The rest of this page covers where the word comes from, what it does and does not tell you, and how these things actually attach to a truck. For parts by truck, go to nerf bars for trucks.

Where the word comes from

Nerf bars started on the track. Wikipedia describes a nerf bar as a tubular device on the side of a race car, usually a single-seater on an asphalt or dirt oval, there to keep tires from tangling when cars touch. The same article uses the word for a small bump between two cars during a pass.

It lists two other uses. On quad bikes, the bars help stop the wheels of two machines from tangling. On a pickup or SUV, it calls them a convenience: a step for getting in and out that can also shield the body over rocks. Wikipedia does not say where the word itself comes from, and we found no sourced answer.

What the word tells you, and what it does not

The word tells you less than you would think. Truck listings stack these names on top of each other:

• The Tyger title for TG-SS2C35068 says "Running Boards" and "Side Step Rail Nerf Bars" for one part.
• Tyger's own sheet for TG-SS2D35098 has "Step Bars" in its header, while the listing title calls that part Rider Running Boards with "Nerf Bars" at the end.
• The APS title calls a flat, 6-inch black stainless board "Running Boards Nerf Bars".
• Westin's catalog sells "Oval Nerf Bars", "Drop Nerf Bars" and "Nerf Step Bars" in one category with its running boards.

So the name is no guarantee of the shape. On the listings we compare, tube-style nerf bars run from 3 inches (MaxMate) to 3.5 inches (Tyger Rider), and the flat parts sold under the same word are about 6 inches. Read the shape and width in the title. Check your exact year and cab on the listing before you buy.

If you are weighing the styles against each other, see nerf bars vs running boards, nerf bars vs side steps and running boards vs side steps.

How nerf bars mount

Here is the part most explainers skip. A nerf bar does not bolt straight to the truck. It sits on brackets, and the brackets attach at points built into that truck's body, so each part follows one truck's layout. We read four Tyger instruction sheets for crew cab rails, and each one does it differently:

Read 2 November 2026. These are four parts, not a rule for all nerf bars. Fit in the first column is as the listing states it.

Three things stand out.

The attachment point changes by truck. That is the reason a bar for one truck will not go on another, even when both are called crew cabs. Each part is built for specific model years and cabs, sometimes bed lengths.

None of these four sheets mentions the frame. They all attach to the body: the bottom edge, the panel sidewall or the pinch weld. Other brands may do it differently, so do not take "bolt-on" to mean frame-mounted. If frame mounting is what you are after, read heavy-duty running boards and the rock slider comparison.

"No-drill" is not automatic. Tyger's older Ram sheet says 2009-12 models may not have factory holes in the pinch weld and will need drilling there. The other three sheets have no drilling step, and Westin says "no drilling required for most applications" about its HDX Drop bars. "Most" is the honest word.

Three of the four sheets say assistance is recommended. Two of them note that a step pad sits closer to one end of the bar, so identify the correct side before you lift it. Our install guide has the general job, and your own sheet has the final word.

What nerf bars will hold

No shared number exists, so do not trust anyone who gives you one for nerf bars in general. The four Tyger sheets above state no weight rating. A missing rating means it was not stated, and it says nothing about what the part can hold. We print a rating only from the maker's own document, and how much weight running boards can hold collects the ones we have read.

Are they right for your truck?

Go tube if you want a slim line along the cab and do not need a big foot area. Go wider if you or your passengers want more room to plant a boot. Go with a drop style if the first step is the problem. The bar itself is the easy choice. Finding the listing that names your year and cab is the real work.

Start at nerf bars for trucks for our picks, or go to all trucks and work down from your make. How we verify fitment explains why every fit line here is a quote and never our own conclusion.