RGN vs Step Deck vs Flatbed: Which Trailer Does Your Equipment Need?
One of the most common questions equipment buyers, dealers, and contractors ask when booking a heavy-haul move is: "What kind of trailer do I need?" The answer depends on three factors — your equipment's height, its weight, and how it gets loaded onto the trailer. Getting this wrong can mean a failed inspection, a permit violation, or damage to your machine. This guide breaks down the three most common trailer types for heavy equipment and explains exactly when to use each one.
The Three Main Trailer Types for Heavy Equipment
Most heavy equipment moves in the United States use one of three trailer configurations: flatbed, step deck (also called drop deck), or RGN (Removable Gooseneck, also called a lowboy). Each has a specific use case, and understanding the differences helps you communicate clearly with carriers and avoid surprises at pickup.
Flatbed Trailers
A flatbed trailer is the simplest and most common trailer type. It's a flat, level deck with no sides or roof, typically 48 or 53 feet long. The deck sits approximately 5 feet off the ground.
- Best for: Equipment that fits within legal height limits (under 8.5 ft tall when loaded) and can be crane-loaded or loaded with a forklift. Common examples: skid steers, compact track loaders, small generators, and construction materials.
- Weight capacity: Typically 48,000–52,000 lbs payload.
- Loading method: Requires external lifting equipment — a crane, forklift, or loading dock. The flat deck has no ramps.
- Permit implications: If your equipment fits within legal dimensions (8.5 ft wide, 13.5 ft tall, 80,000 lbs GVW), no oversize permits are required. This makes flatbeds the most cost-effective option when the equipment qualifies.
- When NOT to use a flatbed: If your equipment is taller than 8.5 ft when loaded on a flatbed, or if it's self-propelled and can't be crane-loaded safely, you need a different trailer.
Step Deck (Drop Deck) Trailers
A step deck trailer has two deck levels — a short upper deck near the cab and a longer lower deck that drops down, providing more vertical clearance than a flatbed. The lower deck typically sits 3.5 to 4 feet off the ground, giving you an extra 12 to 18 inches of height compared to a flatbed.
- Best for: Equipment that is too tall for a flatbed but doesn't require ground-level loading. Common examples: backhoe loaders, telehandlers, medium-size excavators (under 20 tons), and some asphalt pavers.
- Weight capacity: Typically 42,000–48,000 lbs payload on the lower deck.
- Loading method: Most step decks use ramps for loading. The equipment drives up the ramps onto the lower deck. Some step decks can also be crane-loaded.
- Permit implications: If your equipment is 9–10 ft tall when loaded on a step deck, you may still be within legal height limits (13.5 ft total). This can avoid height permits while still accommodating taller equipment than a flatbed allows.
- When NOT to use a step deck: If your equipment is very heavy (over 48,000 lbs), very tall (over 10 ft), or self-propelled without good ramp access, you likely need an RGN.
RGN (Removable Gooseneck) Trailers
An RGN trailer — also called a lowboy or detachable gooseneck — is the workhorse of heavy equipment transport. The front gooseneck section detaches from the trailer deck and lowers to the ground, creating a ramp that allows self-propelled equipment to drive directly onto the deck. The deck sits approximately 18 to 24 inches off the ground when loaded.
- Best for: Large, heavy, self-propelled equipment that cannot be easily crane-loaded. Common examples: excavators (20+ tons), bulldozers, motor graders, large cranes, and mining equipment.
- Weight capacity: Highly variable based on axle configuration. Standard RGNs handle 40,000–80,000 lbs. Multi-axle RGNs can handle 150,000+ lbs for superloads.
- Loading method: The gooseneck detaches and lowers to the ground. The equipment drives up the ramp and onto the deck. No crane required for most machines.
- Permit implications: RGN loads almost always require oversize permits due to the equipment's weight and dimensions. However, the low deck height helps keep the loaded height within legal limits for many machines that would be too tall on a flatbed or step deck.
- When NOT to use an RGN: For small, light equipment that can be crane-loaded and fits within legal dimensions, an RGN is overkill and more expensive than necessary.
The Decision Framework: How to Choose
Use this three-step process to determine the right trailer for your equipment:
- Measure the height: How tall is your equipment? Under 8.5 ft → flatbed may work. 8.5–10 ft → step deck likely needed. Over 10 ft → RGN or lowboy required.
- Check the loading method: Can your equipment be crane-loaded safely? If yes, flatbed or step deck are options. If it's self-propelled and crane-loading is impractical, you need an RGN.
- Verify the weight: Is the equipment over 48,000 lbs? If yes, step decks and flatbeds may not have sufficient payload capacity. RGN trailers scale up with additional axles to handle the heaviest loads.
Common Equipment and Their Typical Trailers
| Equipment | Typical Trailer | Notes |
|---|---|---|
| Skid steer / CTL | Flatbed or Step Deck | Usually within legal dimensions |
| Backhoe loader | Step Deck | Cab height often exceeds flatbed limits |
| Mini excavator (under 8 ton) | Step Deck or Flatbed | Depends on height with cab raised |
| Mid-size excavator (8–20 ton) | Step Deck or RGN | Weight and height determine choice |
| Large excavator (20+ ton) | RGN / Lowboy | Weight and self-propelled loading |
| Bulldozer (D6 and larger) | RGN / Lowboy | Weight and blade width |
| Motor grader | RGN / Lowboy | Blade width and weight |
| Telehandler | Step Deck | Boom retracted, usually fits |
| Large crane (all-terrain) | Multi-axle RGN | Superload — multiple trailers |
Not sure which trailer your equipment needs? IronHaul Logistics will assess your machine's dimensions and recommend the right trailer and permit strategy. Call (208) 495-2260, email [email protected], or fill out our online quote form — we'll get back to you with a recommendation and quote within hours.
Common questions
What is the difference between an RGN and a lowboy trailer?
RGN (Removable Gooseneck) and lowboy are often used interchangeably, but technically an RGN has a detachable front gooseneck that lowers to the ground for drive-on loading, while a traditional lowboy has a fixed gooseneck and requires ramps or crane loading. In practice, most carriers use 'lowboy' and 'RGN' to mean the same thing — a low-deck trailer for heavy equipment.
Can a skid steer ship on a flatbed?
Yes, most skid steers and compact track loaders ship on flatbed or step-deck trailers. They are typically within legal height limits and light enough for flatbed payload capacity. A crane or forklift is used to load them onto the flatbed.
When does an excavator need an RGN instead of a step deck?
Excavators over about 20 tons typically need RGN trailers due to weight (exceeding step-deck payload capacity) and the practical difficulty of crane-loading a large, heavy machine. Smaller excavators (under 15 tons) can often ship on step decks with ramps.
Does the trailer type affect permit requirements?
Yes. The trailer type affects the loaded height, which determines whether height permits are needed. An RGN's low deck height can keep a tall machine within legal height limits, avoiding height permits. A flatbed's higher deck can push the same machine over the legal height limit, triggering permits.
How do I tell a carrier which trailer I need?
Provide the carrier with your equipment's make, model, operating weight, and dimensions (length, width, height with cab in travel position). The carrier will determine the appropriate trailer based on these specs and the route requirements. If you're unsure of the dimensions, the carrier can often look them up from the manufacturer's spec sheet.
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