Aluminum vs. Steel Truck Beds: Weight, Strength, Cost & Rust Compared

Aluminum truck beds are significantly lighter than steel beds and don't rust, while steel beds usually cost less up front and are stiffer at the same thickness. By volume, aluminum weighs about one-third as much as steel, and a common structural alloy like 6061-T6 has a yield strength in the same range as A36 structural steel. For most working trucks, that adds up to more usable payload and less corrosion upkeep. Steel still makes sense when the lowest purchase price matters most or the bed takes constant hard impact.

Below is a side-by-side comparison using published material properties, followed by what those numbers mean once the metal becomes a flatbed or stake bed on a real truck.

Aluminum vs. steel at a glance

Is aluminum lighter than steel?

Yes, by a wide margin. Aluminum has a density of about 2.70 g/cm³ (roughly 169 pounds per cubic foot), while carbon steel is about 7.85 g/cm³ (roughly 490 pounds per cubic foot). Put simply, the weight of aluminum vs. steel for the same volume is about one to three.

That ratio doesn't carry straight through to a finished bed. Because aluminum is less stiff, designers use thicker sheet and deeper structural sections, so an aluminum bed is not one-third the weight of a steel bed. It is still significantly lighter. Our aluminum beds are up to 50% lighter than steel and wood beds, and every pound taken off the bed is a pound of the truck's rated capacity you can put back into cargo.

Is steel stronger than aluminum?

It depends on which kind of "strong" you mean, and the difference matters for truck beds.

• Stiffness: steel wins. Its modulus of elasticity is about 29,000 ksi versus about 10,000 ksi for aluminum, so an identical aluminum part flexes about three times as much under the same load.
• Yield strength: closer than most people expect. 6061-T6 aluminum has a typical yield strength of about 35–40 ksi, and A36 structural steel is about 36 ksi. Higher-strength steels go beyond that.
• Strength for the weight: aluminum comes out ahead. Similar yield strength at about one-third the weight means a well-designed aluminum structure can carry serious loads without the dead weight.

That's why aluminum vs. steel strength isn't a simple yes-or-no question. Aluminum beds make up for lower stiffness with geometry: deeper crossmembers, thicker sections and shapes that put metal where the loads are. Our beds sit on heavy-wall aluminum C-channel or I-beam crossmembers, and the floor carries an 8,000 lb distributed load rating, which in most cases is more than the truck's GVWR. Your truck's own payload, GVWR and axle ratings always set the real limit.

One honest trade-off: at the same thickness, aluminum dents more easily than steel, which is another reason aluminum parts are made thicker.

Does aluminum rust? Corrosion compared

Aluminum does not rust. Rust is iron oxide, which forms on iron and steel exposed to water and oxygen. Aluminum reacts with oxygen too, but it forms a thin, tight oxide layer that protects the metal underneath. Bare aluminum dulls to a gray finish over time; it doesn't flake away the way rusting steel does.

Steel needs a coating, such as paint, powder coat or galvanizing, to hold off rust. Once tools, chains or gravel chip that coating, the exposed steel can start to rust, and rust tends to creep under the surrounding finish.

Aluminum isn't immune to every kind of corrosion. When it touches a dissimilar metal, like plain steel hardware, in the presence of moisture, galvanic corrosion can attack the aluminum. Strong acids and strong bases also attack it. That's why hardware matters: our gate hinges are 304 stainless steel, latches and locking pins are stainless steel, and stainless steel hardware is used on our pool truck beds and available for wet or cold climates. For upkeep tips, see our guide to aluminum bed winter maintenance.

“I've purchased metal truck beds in the past but have never been satisfied — I always had to deal with rust and corrosion.”

— Lindsey, Fabulous Flowers

Is aluminum more expensive than steel?

Yes. Aluminum costs more per pound than steel, and an aluminum truck bed usually costs more up front than a comparable steel bed. That's the straightforward answer on steel vs. aluminum cost.

What the difference buys is lower weight and no rust: no rusted floor or crossmembers to repair, and no paint to keep up just to hold off corrosion. Whether that's worth it depends on how hard the truck works, how long you plan to keep it and where it lives. The price of any bed also depends on its size, gates, tool boxes and options (see what affects aluminum truck bed prices), which is why we give a firm quote by email or text within 2 business days instead of a ballpark.

Malleability: how aluminum and steel are shaped

Malleability is a metal's ability to be pressed, rolled or hammered into shape without cracking. The malleability of aluminum is high, which is why it can be rolled into thin sheet and pushed through a shaped die to make extrusions: long pieces with a constant cross-section, such as channels, I-beams, tubes and gate frame profiles.

Steel's formability depends on its grade. Low-carbon (mild) steel bends and forms well, while higher-carbon steels are harder and less forgiving. Steel is usually rolled, bent or stamped into shape. For a truck bed, extrusion makes it practical to use purpose-made aluminum shapes, like the 6061-T6 aluminum extrusion in our gate frames. We cover alloys and tempers in our aluminum alloy guide.

What it means for a working truck bed

• More payload. Payload is what's left of the truck's GVWR after the truck itself, bed included, is weighed. A lighter bed leaves more of that rating for tools and material.
• No rust where water sits. Floors, stake pockets and crossmembers collect water, dirt and road salt. On aluminum, those spots don't rust.
• Hardware choices matter. Stainless steel hinges, latches and pins don't rust and reduce the risk of galvanic corrosion compared with plain steel hardware.

Aluminum truck bed pros and cons

Why aluminum is the standard for truck beds

1. It's lighter. About one-third the weight of steel by volume, so the finished bed is significantly lighter and leaves more payload.
2. It doesn't rust. Its oxide layer protects the metal without paint.
3. It's strong for its weight. 6061-T6 has a yield strength in the same range as A36 structural steel at about one-third the weight.
4. It extrudes into efficient shapes. Channels, I-beams and gate frame profiles put metal where the loads are.
5. It's low maintenance. Regular washing does most of the work; there's no rust to grind out and repaint.
6. It looks good bare or finished. Bare aluminum weathers to a dull gray, and it can be powder coated if you want a color.
7. Truck makers use it too. The Ford F-150 (2015 and newer) and Super Duty (2017 and newer) have aluminum bodies and beds on steel frames. See which trucks have aluminum bodies.

The trade-offs

• Higher up-front cost than a comparable steel bed.
• Less stiff than steel, so parts are thicker and deeper to compensate.
• Dents more easily than steel of the same thickness.
• Repairs need an aluminum-capable welder, and welding heat lowers strength near the weld in heat-treated alloys.
• Can corrode galvanically if paired with the wrong hardware in wet conditions.

When steel still makes sense

Steel is a reasonable choice in some situations:

• The lowest purchase price is the top priority, and the truck has plenty of payload to spare.
• The bed takes constant hard impact, such as rock, scrap or demolition debris dropped from a height, where steel's stiffness and hardness at a given thickness help.
• You want repairs that almost any welding shop can handle on short notice.
• The truck lives in a dry climate, won't be kept long, and corrosion isn't a big concern.

If none of those describe your truck, aluminum is usually the better long-term fit. If you're weighing the two, call us at (714) 602-6970, Monday through Friday from 8:00 AM to 4:00 PM, and tell us how the truck is used.