Running Boards vs Nerf Bars vs Rock Sliders: Which Step Fits How You Use Your Truck

How we made this guide: picks and specs come from our catalog and fitment data, owner quotes come from verified reviews and the guide was drafted with AI help, then checked and edited by Trevor Hall.

Pick running boards for a daily driver, nerf bars when the climb in is the problem and rock sliders only off-road. For most trucks that means the Go Rhino Dominator D6 running board (from $609.99, listed for 12 of our truck lines) or the N-Fab Predator Pro nerf bar (from $729.99), an aluminum bar that fits 14. For the trail, the N-Fab RKR Step System (from $649.99) has steps that unbolt.

The names overlap, so judge a part by its build. A running board is a wide, flat step along the cab. A nerf bar, also sold as a step bar, is a tube with a step plate at each door. A rock slider is a heavy tube that takes the hit so the rocker panel does not. Every nerf bar we carry is under $800 and the electric running boards we carry start at $1,599.99. The From prices below are each series' starting price, unless a truck is named.

The five types side by side

Warranty and ratings by series

What the names mean

Go Rhino titles the Dominator D6 a running board and the D1 a side step, yet its own part names call the D6 and the DSS Dominator Xtreme side steps too. The DSS is called a slider but is built as a step with a rub rail. N-Fab calls its RKR rock rails, while our catalog files it as a rock slider. So the label tells you little: compare step width, tube size and mount.

Running boards: a wide step that stays close to the body

The Go Rhino Dominator D6 pairs a tubular carbon steel frame with a 6 inch plate steel pad that has a raised hex grip. Most kits mount at the rocker panel without drilling; frame-mount kits need drilling.

In its owner reviews the install is the complaint: several call it slow or awkward, and one logged four hours against an expected hour and a half. One 2-star owner also found rust on the boards straight out of the package.

“I purchased these steps because I liked the tough look and because they were up close/tight to the rocker panel. I didn’t want a step that hung too low.”

Go Rhino Dominator D6 Running Boards owner · 4 out of 5 stars

Skip the D6 if you need a lower first step on a truck with lower rocker panel extensions: Go Rhino's 4 inch drop steps are sold separately and do not fit those models.

The N-Fab Roan is the other steel board: a tubular steel frame under a 5.5 inch, 12-gauge steel plate with raised louvers, rated at 475 lb. Its brackets use existing holes in the rocker panel, so nothing is drilled.

One owner on a 2018 Ram 1500 Sport found a nut welded into the body that the instructions never mention. They ran the boards on five of the six mounting points and found them solid after two months. Skip the Roan if your truck is not a crew cab or CrewMax, the only cabs its fit table lists.

Nerf bars and side steps: a step plate at every door

A nerf bar swaps the long plate for a tube along the rocker with a step plate dropped at each door, which puts the first step lower for kids, short drivers and lifted trucks. Nerf bars come cab length (a step at each door) or wheel to wheel (running back to the rear wheel, with an extra step for reaching into the bed), so check the length on the part you pick. The N-Fab Predator Pro is welded from extruded aluminum as one piece with a 4 inch raised-slot step at each door.

Skip the Predator Pro if you plan to put the bar on rocks. One 4-star owner called the instructions terrible, so read the guide for your part number first.

The N-Fab Nerf Step RS is the steel alternative: a 2 inch tube that hugs the rocker with 4.75 inch dimpled step plates rated at up to 300 lb per step. Among our truck lines it is listed only for the Ram 1500 and the Ram 2500 and 3500, from $639.99; on other trucks, look at the Predator Pro. The step plates hang lower than the rocker line, so tight trails will find them first.

“These steps are sporty and very handy for kids. I was okay grabbing my steel bar and jumping in but I had to always pick my kids up. Therefore, steps were a must!”

N-Fab Nerf Step RS Step Bars owner · 5 out of 5 stars

Skip the RS if you drive salted winter roads and will not rinse the bars and touch up chips.

Go Rhino's Dominator D1 side steps sit between the two: a tubular steel frame with a 5.5 inch dimpled plate-steel tread the full length of the cab. Our listing says they shield the rockers from kicked-up rocks but are side steps rather than dedicated rock sliders.

“Installing was another story. Easier for 2 people, next to impossible for 1 at least on my truck.”

Go Rhino Dominator D1 Side Steps owner · 5 out of 5 stars

Skip the D1 if you will install alone. Several owners say the brackets need a second person, and reports run from under an hour with a helper to about four hours. Four owners also report some flex or a downward lean underfoot. Another received a set with chipped powder coat twice.

Rock sliders: armor first, step second

A rock slider is built to take contact. N-Fab builds the RKR rails from 1.75 inch steel tube with a .120 inch wall to guard the rocker panels on the trail, and no load rating is published for them. In the Step System, 3 inch hoop steps bolt to the rails for daily use and come off for the trail.

“It offers protection for the under carriage and rocker panels if I ever stray off the trails. Wish they stuck out a bit further though to offer more protection. The removable steps are sturdy, but they could be a tad wider IMO.”

N-Fab RKR Step System Rock Sliders owner · 5 out of 5 stars

The complaints in the 11 RKR reviews are about install and reach: a heavy rail, a hard-to-reach bottom bolt and rails that stick out too little. Skip it if you want more projection.

Go Rhino's Dominator DSS is the in-between: a full-length slider with an outer rub rail and a bolt-on 2 inch dimpled steel step pad, tucked high and tight to the body. Go Rhino says it is not as durable as a dedicated rock slider. It does guard the rockers against kicked-up rocks and road debris. Skip it if rock strikes are your main worry.

Do running boards work as rock sliders?

Mostly no. Our Predator Pro listing calls it a step and rocker guard rather than a slider. Our D6 listing pitches the board as a step and slider in one for rock chips, abrasion and mild impacts, so read mild as the limit. The load ratings on the Roan (475 lb) and the RS (300 lb per step) describe the step, not a slider rating.

Are rock rails and rock sliders the same thing?

Often, yes. Both names describe a tube along the rocker that takes rock contact, and N-Fab calls its RKR rock rails while our catalog files it as a rock slider. The name does not tell you the strength, so check the tube, the wall and the mount: Go Rhino says its frame-mount DSS versions add strength. None of our listings gives a load rating for these rails.

Do nerf bars rust?

Steel can, once the powder coat is breached. The N-Fab Nerf Step RS is mild steel under textured black powder coat. In the 200 owner reviews on file for it, 19 report rust, most inside the first year and several at the welds or seams.

“Had them less than two months and already showing signs of rust around the welds.”

N-Fab Nerf Step RS Step Bars owner · 1 out of 5 stars

The Predator Pro is extruded aluminum, which does not form red rust. None of its 84 reviews on file reports rust, but three owners report chipped powder coat, one after a car wash. Our listing notes that aluminum can still form white surface corrosion where salt sits on a chip. The D1, D6, DSS, Roan and RKR are steel, so rinse salt off through winter and touch up chips when you see them.

Both makers back the finish for five years. Go Rhino's limited 5-year finish warranty covers red rust, peeling, flaking and cracking for the original owner, on top of a limited lifetime structural warranty. N-Fab warrants its textured black powder coat for five years and the part itself for life against defects, for the original buyer on the vehicle it was first fitted to. Rust inside five years is a warranty question, so keep the receipt.

Are nerf bars universal? Fit and install

No. N-Fab's brackets are specific to each vehicle. Go Rhino builds each Dominator kit for named vehicles and cabs, and the D1 alone is sold as 24 listings here. Fit notes narrow it further: the Roan lists crew cabs only, some 2011 to 2019 Silverado and Sierra HD parts in the D6 table are gas engine only and the DSS fit notes exclude some vehicles by factory equipment. Match year, cab and engine with Check fit for your truck on any product card before you order.

Most of these bolt to existing holes or factory mounting points with hand tools. A few D1 and RS applications call for a small hole. A few rocker-mount D6 kits ask for existing holes to be enlarged. Frame-mount D6 and DSS kits require drilling. Owners report about an hour to four hours for a pair.

Electric running boards: steps that fold away

If you want nothing hanging below the door, an electric running board folds away until a door opens. The AMP Research PowerStep (from $1,599.99) uses one Brose motor per side, brings a 6 inch aluminum step down and out and stops if something blocks it. On most of our truck lines it starts at $1,599.99, and Go Rhino's VoltStep, the other electric board we carry, starts at $1,399.99 on 10 of our truck lines. The PowerStep bolts to the pinch weld and needs a wiring harness. Compare the lineup in our guide to the best electric running boards, and see PowerStep problems and fixes if one stops working.

Which step fits how you use your truck

Frequently asked questions

What is the difference between side steps and running boards?

Mostly the name. A running board is a wide, flat step along the cab. Side step is a looser label that makers use for flat steps and tube steps alike: Go Rhino's D1 side step and D6 running board are both a plate-steel tread on a tubular steel frame, 5.5 and 6 inches wide. A nerf bar is the one built differently: a tube along the rocker with a step pad at each door, 4 to 4.75 inches wide on the N-Fab bars.

Do nerf bars rust?

Steel ones can: 19 of the 200 owner reviews on file for the N-Fab Nerf Step RS report rust, mostly within a year. The aluminum Predator Pro does not form red rust.

How much does it cost to have running boards put on your truck?

Shop labor varies by shop and truck, so ask for a written quote. Owners who install at home report about an hour to four hours for a pair. The AMP PowerStep is a wiring job that the spec sheet says calls for an experienced or professional installer.

What are the downsides of running boards?

They cost some ground clearance. The step plate is usually the lowest point, so it is the first thing to meet a rut or rock. Steel boards need rinsing through salted winters: 19 of the 200 Nerf Step RS reviews on file report rust. Owners report about an hour to four hours to fit a pair, and several D6 and D1 owners call the install slow or awkward.

Related guides

• Best Electric Running Boards: AMP PowerStep Lineup vs Go Rhino VoltStep
• AMP Research PowerStep Problems: Causes, Fixes and How to Reset