What Is a Double Drop Trailer and When Should You Use One?

What Is a Double Drop Trailer?

A double drop trailer, sometimes called a double drop deck trailer or lowboy trailer, combines two step-down drops between its loading areas. The front deck sits slightly above the trailer’s neck, the middle (or lower) deck dips close to the ground, and the rear deck raises again near the axles.

This layout lets the trailer carry taller loads while staying within height limits. Equipment like construction gear, industrial machinery, or large generators typically can’t travel on a flatbed trailer or even a step deck trailer without exceeding legal tall-load limits. The lower deck gives several additional inches, or even feet, of clearance, making transport more practical and safe.

When and Why Double Drop Trailers Are Used

Double drop trailers are a smart solution for shippers who need to move freight that simply won’t fit on a standard flatbed or step deck. Because of their design, these trailers are often used for specialized cargo in construction, manufacturing, and energy sectors.

Best Use Cases for Double Drop Trailers

Heavy Equipment: Bulldozers, Excavators, Backhoes

Bulky, self-propelled machines like bulldozers, excavators, and backhoes often exceed standard height restrictions when loaded onto flatbeds or step decks. A double drop trailer gives these machines the clearance they need by placing them closer to the ground. This avoids the need for excessive permitting and keeps the load stable during transit, which is especially helpful for jobs that involve uneven terrain or longer hauls.

Construction Gear: Cranes, Dumpers, Large Scaffolding

Construction equipment comes in many shapes and sizes, and when it’s large and tall, like mobile cranes, dump trucks, or oversized scaffolding, double drop trailers make it possible to move this gear without major modifications. The lower deck gives enough space for height, while the reinforced structure supports the heavy weight often associated with these types of cargo.

Industrial Machinery: Large Pumps or Presses

Industrial facilities rely on heavy-duty machines that are often both tall and dense, such as hydraulic presses, industrial dryers, or giant pumps. A double drop trailer can safely support and carry these oversized pieces, especially when paired with a removable gooseneck (RGN) that allows front-loading.

Any Load Taller Than What Flatbeds or Step Decks Can Handle

Standard flatbeds and step decks usually can’t accommodate anything taller than about 8.5 to 10 feet. If your cargo exceeds that, you’ll either need expensive permitting or a trailer type that accommodates extra height. Double drops are specifically designed to keep loads under height limits by using the recessed lower deck section for the tallest part of the cargo.

Why Opt for a Double Drop Trailer?

1. Keeps Height Within the Legal Limit: The lower deck design allows taller cargo to ride closer to the ground. This keeps the total load height within the legal maximum.
2. Reduces Permitting Requirements for Oversized Loads: By naturally accommodating tall equipment, double drop trailers help avoid excess permits that would otherwise be needed with flatbeds or step decks.
3. Supports Front Loading with Removable Gooseneck (RGN) Options: Some double drop trailers are equipped with removable goosenecks, making it possible to load heavy machinery by driving it on from the front.

Double Drop vs Other Trailer Types

Trailer Type	Deck Height	Ideal For	Benefits	Notes
Flatbed Trailer	~60 inches	Pallets, containers	Common, accessible equipment	No drop decks
Step Deck Trailer	38–42 inches	Mid-sized equipment	Lower deck than flatbed	Single drop deck
Double Drop Trailer	18–24 inches	Tall or heavy machinery	Great vertical clearance	Multiple drops
RGN Trailer	Detachable front	Self-propelled machinery	Allows front drive-on loading	Removable gooseneck variant

Parts of a Double Drop Trailer Explained

Upper Deck

This raised front section attaches over the truck’s rear axles. It serves as the landing zone for equipment extending forward or additional support cargo. The upper deck is typically used for smaller items, toolboxes, tarping supplies, or components that don’t require the lower height clearance. It also helps balance the load across the trailer for better weight distribution.

Lower Deck (Main or Bottom Deck)

Here’s where the main cargo sits – the deck closest to the ground. It carries the heaviest or tallest gear, keeping transport height low. This sunken section is the reason double drop trailers are preferred for tall loads that exceed height limits on flatbeds or step decks.

Rear Deck

This rear transition sits just before the axles. It offers support and distributes weight as cargo nears the end of the trailer. Though not as low as the main deck, the rear deck helps stabilize longer equipment that extends beyond the center portion. In some configurations, this section may include ramps or be engineered for additional load-bearing strength.

Trailer Dimensions and Weight Capacity

Construction specs often vary depending on design and regulation, but these are common figures:

Specification	Typical Range
Lower Deck Height	18–24 inches
Lower Deck Length	25–29 feet
Overall Trailer Length	48–53 feet
Width	8.5 feet (standard)
Weight Capacity	40,000–80,000+ lbs (by axle setup)

Exact measurements can vary, particularly with choices in axles, reinforcements, or custom builds. Always check specs before hauling heavy gear.

What Is a Removable Gooseneck (RGN)?

A removable gooseneck (RGN) trailer is a specific type of double drop trailer designed with a detachable front section, called the gooseneck. This gooseneck can be lowered to the ground, creating a ramp so heavy machinery can be driven directly onto the main deck (also called the bottom deck). This feature is especially helpful when cranes or loading docks aren’t available or practical.

• Gooseneck trailer: The front connects to the fifth wheel of the tractor, with no drop-off
• Removable gooseneck: Front drops down for direct loading
• Great for construction equipment or industrial machines

By removing the need for external loading equipment, RGN trailers offer flexibility on job sites or in remote areas. However, not every load requires this type of access, and not every double drop trailer includes it.

Is a Removable Gooseneck Required for All Double Drop Trailers?

No, not all double drop trailers have a removable gooseneck, and many hauls don’t need one. The choice depends on how the cargo is loaded and what kind of access the pickup and drop-off locations offer.

What Is the Difference Between a Double Drop and a Step Deck Trailer?

A step deck trailer, also called a single drop, has one lowered portion between the front pull-up and the rear upper deck. It’s lower than a flatbed, but not as low as a double drop.

A double drop adds another dip between the front and back, pushing the central deck even closer to the ground. This makes it ideal for taller loads that can’t fit on step decks. If a load hits height limits on a step deck trailer, a double drop usually solves that.

Can Double Drop Trailers Handle Oversized Permits?

Yes. Double drop trailers handle oversize loads well. Though regulations vary by state, most define oversize as:

• Loads over 13’6” in height
• Over 8’6” wide
• Over certain length or weight thresholds

Because the lower deck design reduces overall height, many loads fall under standard limits without permit requirements. But for exceptionally large freight, permits are still needed.

Always confirm local rules before hauling tall machinery. The right trailer may cut down permit complexity and cost.

Learn About Oversized Regulations by State

What’s the Maximum Height I Can Haul on a Double Drop?

The maximum height depends on the trailer’s deck height and local legal limits. With a lower deck around 18–24 inches off the road, double drop trailers often carry:

• Up to 11’6” above the road surface, depending on lower deck position and truck bed height

In many states, the standard height limit is 13’6”. The lower deck means a load that tall may need less clearance space or fewer obstacles.

Truck bed height and gooseneck mounting also matter, so always measure before hauling. And remember, permit rules still apply if height goes over state limits.

What Types of Cargo Are Not Suitable for Double Drop Trailers?

Double drop trailers aren’t the best choice for:

• Small, palletized goods (ideal for flatbeds or vans)
• Low-weight items where a lower deck isn’t needed
• Cargo that fits height limits for standard trailers already

When the load doesn’t need the bottom deck benefit, simpler trailers are easier and often cheaper.

Advantages of Using a Double Drop Deck Trailer

Double drop deck trailers offer several practical advantages for hauling oversized, heavy, or unusually tall cargo. When standard trailers aren’t up to the task, a double drop provides the extra clearance and support needed for safe and legal transport.

#1 Keeps cargo height below legal thresholds

The lowered main deck allows taller items to be loaded without exceeding federal and state height restrictions.

#2 Handles heavy or tall freight like construction equipment or industrial gear

These trailers are built for the weight and dimensions of bulldozers, large generators, press machines, and other bulky equipment.

#3 Ground clearance keeps the center of gravity low, improving stability

Lower cargo placement helps reduce sway and increases control, especially on long-distance hauls or uneven roads.

#4 Can be fitted or modified into a custom trailer for unique loads

Some models can be tailored to fit specialized cargo requirements, including extra-long decks, added axles, or removable goosenecks for front-loading.

Mercer Transportation’s Double Drop Hauling Services

Mercer Transportation brings experience and a strong safety record to double drop hauling. 

Here’s what we offer:

• Nationwide service for heavy, tall, and industrial equipment
• Dedicated fleet that includes over 600 drop deck trailers
• Skilled operators with training in oversized loads

Mercer focuses on safe delivery and makes hauling large items easier for your project. Our equipment and staff reduce risks and logistical headaches, especially for freight that pushes size limits.