Stepdeck Trailers: The Perfect Solution for Oversized Freight

Hauling oversized or tall cargo? The right equipment isn’t just important—it’s everything.

Designed to handle big loads while staying within legal height limits, step deck trailers give you the flexibility that traditional flatbed trailers just can’t match.

• What is a Step Deck Trailer?
• What Kind of Freight is Typically Carried on Step Deck Trailers?
• Step Deck Trailer Dimensions and Weight Limits
• Alternatives to Step Deck Trailers
• Pros and Cons of Shipping with Step Deck Trailers
• Step Deck Shipping Tips

What is a Step Deck Trailer?

A step deck trailer, also known as a drop deck trailer, is a specialized flatbed designed to accommodate taller cargo without exceeding legal height limits. It features two deck levels—an upper deck positioned above the tractor’s fifth wheel and a lower deck that drops down to a level below the upper deck. This structure allows for the safe transport of oversized loads, including construction equipment and other large items that wouldn’t fit legally on a standard flatbed trailer.

View Legal Height Limits for Commercial Motor Vehicles 

Main Features and Characteristics

Step deck trailers are built to handle a wide range of loads that require extra height clearance. The lowered deck provides additional vertical space, making it possible to transport tall cargo without requiring special permits for excessive height.

Some key characteristics include:

• Two deck levels for greater flexibility in loading and securing freight.
• A lower deck that accommodates maximum cargo height while staying within federal height regulations.
• Multiple length options, with common sizes including 53-foot, 48-foot, and 40-foot trailers.
• Extra axles on some models to support heavier weight capacities.
• Ramp compatibility for easy loading of wheeled equipment like tractors and construction machinery.

What Kind of Freight is Typically Carried on Step Deck Trailers?

Stepdeck trailers’ ability to handle oversized, heavy, or irregularly shaped cargo makes them essential in industries that require specialized transportation solutions.

Some of the most common types of freight transported on step deck trailers include:

• Construction equipment: Excavators, bulldozers, loaders, and other machinery that require extra height clearance.
• Agricultural machinery: Tractors, combines, balers, and irrigation systems.
• Oversized industrial materials: Prefabricated structures, large pipes, wind turbine components, and HVAC units.
• Palletized freight: Large stacks of palletized goods that exceed the height capacity of a standard flatbed trailer.
• Steel and lumber: Heavy-duty industrial materials that need extra support and space during transport.

Step Deck Trailer Dimensions

Step deck trailers come in various sizes to accommodate different types of freight. Choosing the right trailer size depends on the load requirements, cargo dimensions, and transportation regulations.

53-Foot Step Deck Trailer

• Overall length: 53 feet
• Upper deck length: 10-13 feet
• Lower deck length: 40+ feet
• Deck height: 60 inches (top deck), 36 inches (bottom deck)
• Maximum cargo height: 10 feet

48-Foot Step Deck Trailer

• Overall length: 48 feet
• Upper deck length: 10-12 feet
• Lower deck length: 36+ feet
• Deck height: 60 inches (top deck), 36 inches (bottom deck)
• Maximum cargo height: 10 feet

40-Foot Step Deck Trailer

• Overall length: 40 feet
• Upper deck length: 10-12 feet
• Lower deck length: 28+ feet
• Deck height: 60 inches (top deck), 36 inches (bottom deck)
• Maximum cargo height: 10 feet

How Much Weight Can a Step Deck Trailer Haul?

Weight limits depend on the trailer’s axles, but standard step deck trailers typically handle loads up to 48,000 pounds. Additional axles can increase weight capacity. Federal regulations dictate legal weight limits based on axle configurations, so shippers need to verify load capacity before transport. Overloading a trailer can lead to fines, safety hazards, and damage to the equipment.

View Legal Weight Limits for Step-Deck Cargo

Alternatives to Step Deck Trailers

While step deck trailers are a versatile solution for oversized cargo, some shipments require specialized equipment to accommodate even taller or heavier loads. Depending on the freight, shippers may consider these alternatives:

Low-Profile Trailers

Low-profile step-deck trailers have a slightly lower deck height than traditional step decks, allowing for even taller loads while remaining within legal height limits.

Double Drop Deck Trailer

Featuring three levels—an upper deck, a lowered middle section (known as the well), and a rear deck—these trailers are designed for exceptionally tall cargo like industrial tanks, massive pipes, and oversized machinery.

Removable Gooseneck (RGN) Trailers

Equipped with a detachable front section, RGN trailers allow cargo to be driven directly onto the deck, making them ideal for transporting heavy equipment that requires easy loading and unloading.

Pros of Step Deck Trailers

• Accommodates taller cargo while staying within legal height limits – The lower deck provides extra clearance, allowing shippers to transport taller equipment and materials without exceeding federal height regulations. This eliminates the need for costly permits in many cases.
• Easier loading and unloading, especially for equipment – Compared to a standard flatbed, the lower deck height makes it easier to load and unload heavy machinery, reducing the need for additional equipment.
• No special permits are required for standard oversized loads – As long as the cargo height stays within legal limits, step deck trailers avoid the additional paperwork and expenses associated with over-height permits.
• More flexibility than a traditional flatbed trailer – The step deck design allows shippers to haul a wider variety of freight, including large industrial materials, construction equipment, and palletized goods.
• Compatible with a wide range of cargo types – From heavy machinery to steel beams and prefabricated structures, step deck trailers are suitable for industries like construction, agriculture, and manufacturing.

Cons of Step Deck Trailers

• Less deck space compared to a standard flatbed trailer – Because step deck trailers have two levels instead of one continuous surface, they offer slightly less usable deck space, which can be a limitation for certain types of freight.
• May require ramps for wheeled equipment – Unlike RGN trailers that allow cargo to be driven directly onto the deck, step deck trailers often require ramps for loading wheeled machinery such as tractors or bulldozers.
• Some freight may require additional securement – The varying deck heights can make it more challenging to evenly distribute weight and secure cargo, requiring extra attention to tie-down points and load balancing.
• Limited options for side loading – Since step deck trailers have different height levels, loading from the side can be more difficult compared to a standard flatbed, particularly for longer or bulkier freight.

Step Deck Shipping Tips

Transporting freight with a step deck trailer requires proper planning to avoid common pitfalls. 

Here are some practical shipping tips:

1. Know your trailer dimensions: Different step deck trailers have different heights and lengths. Understanding the exact dimensions of your trailer ensures you select the right one for your load and avoid unexpected restrictions.
2. Check maximum height: Even though step decks allow for taller freight, loads must still comply with federal and state height regulations. Exceeding legal limits may require additional permits, increasing costs and potential delays.
3. Use proper securement: Use high-quality straps, chains, and tarps to prevent shifting during transit, especially for irregularly shaped or oversized loads.
4. Plan for loading and unloading: Unlike RGN trailers, step decks do not have a detachable front, meaning some equipment may require ramps for loading. Be sure to account for loading logistics.
5. Follow federal regulations: Step deck trailers must comply with weight, height, and axle distribution regulations. Double-check that your load meets legal requirements to avoid fines or transportation issues.
6. Consider weather conditions: Certain cargo may need additional protection from rain, wind, or extreme temperatures. Plan ahead with tarps or enclosed transport if necessary.

Ship Oversized Freight With Mercer Transportation

Mercer Transportation is your trusted partner for step deck freight across the United States. Whether you’re hauling heavy equipment, oversized loads, or specialized cargo, our experienced team guarantees safe and efficient transport. With a nationwide network of professional owner-operators and a fleet of step deck trailers, we provide reliable transportation solutions for your specific requirements.