Wheel Well Tool Box vs Fifth Wheel Tool Box | The Real Bed Fit

If you’re choosing storage for your truck bed, the distinction between a wheel well box and a fifth wheel box is simple but critical. Both add organized storage, but they serve entirely different situations. A wheel well box tucks into the unused space over a fender well, while a fifth wheel box sits low in the bed so it won’t hit your trailer’s pin box in a turn. Pick based on whether you tow a fifth-wheel or gooseneck hitch, and how much bed space you are willing to lose.

What Is a Wheel Well Tool Box?

A wheel well tool box mounts directly over or around the truck’s wheel well hump, usually up against the side of the bed and often ahead of the tailgate. It uses the dead space that would otherwise be awkward for long or bulky cargo. Many designs include a top-access lid and rear sliding drawers — the UWS UWS01625 for the passenger side, for example, packs 3.9 cubic feet of storage with three drawers and a paddle lock. Most wheel well boxes provide roughly 2 cubic feet and can carry about 75 pounds, though ratings vary. They are side-specific; some must be ordered for the driver or passenger side, and you can flip certain models. Because of their low profile, most fall below the height of a tonneau cover’s mounting rails, though you should confirm fit for the specific box.

What Is a Fifth Wheel Tool Box?

A fifth wheel tool box is a low-profile storage box designed for trucks that run a fifth-wheel or gooseneck hitch. It sits low on the bed floor rather than over a fender well, and it has a sloped or shortened shape so the trailer’s pin box can swing during turns without striking the toolbox. This clearance is critical: you need at least 6 inches of space between the toolbox and the fifth-wheel frame rail or gooseneck ball hole. Some trailers use a pivoting pin box like the Sidewinder or Turning Point that can accommodate a standard box, but you should not rely on that without measuring.

How To Measure Your Truck Bed Before Buying

Whether you choose a wheel well box or a fifth wheel box, these measurements from the pickup truck buying guides will prevent a misbuy. First, measure the exterior bed rail width side-to-side across the top of the bed. Next, measure the interior wheel-well rail width — the distance between the inner rails that sit directly above each wheel well. Then measure the width between the two wheel well humps, and the length from the forward bulkhead to the front edge of the wheel well hump.

Which One Should You Choose?

Choose a wheel well box if you do not tow a fifth-wheel or gooseneck trailer and you want to reclaim the awkward space over your fender wells for small tools and gear. It leaves the middle of the bed open for long items, and most sit low enough to work under a tonneau cover. Choose a fifth wheel box if you tow a fifth-wheel or gooseneck trailer and still need bed storage. It sacrifices some capacity compared to a full-width box but guarantees the clearance needed for safe turning. If you do not tow, a fifth wheel box is less useful — you would give up capacity for a feature you do not need. If you are ready to buy, check our tested roundup of top-rated wheel well tool boxes for specific models that fit your truck and budget.

The table below summarizes the main differences side-by-side so you can decide at a glance.

Three common mistakes sink buyers: picking the wrong side orientation, assuming any toolbox clears a fifth-wheel hitch, and ignoring tonneau cover rails. To avoid all three, measure the bed, decide whether you tow, and match the box design to the clearance requirement.