RGN vs. Lowboy vs. Step-Deck: Choosing the Right Trailer for Heavy Equipment
One of the most common questions equipment buyers and dealers ask is: 'What kind of trailer do I need?' The answer depends on your machine's height, weight, and whether it can be driven onto the trailer. Here's a practical breakdown of the three most common heavy-haul trailer types — RGN, lowboy, and step-deck — so you can have an informed conversation with your carrier.
The Core Problem: Height and Weight
The reason specialized trailers exist is simple: most heavy equipment is too tall to sit on a standard flatbed and still clear bridges and overpasses. A standard flatbed deck sits approximately 58–62 inches off the ground. Add a 10-foot-tall excavator and you're at 18+ feet — well above the 13.5–14 foot clearance limit on most U.S. highways. Specialized trailers solve this by lowering the deck height, giving the equipment more vertical room to work with.
Step-Deck Trailers
A step-deck (also called a drop-deck) has two deck levels: a higher front section that clears the tractor's fifth wheel, and a lower rear section — typically 36–42 inches off the ground — where the equipment rides. This lower rear deck provides roughly 18–24 inches more clearance than a standard flatbed.
Best for: Compact and mid-size equipment that's slightly too tall for a flatbed but doesn't need the ultra-low deck of a lowboy. Skid steers, small excavators, compact track loaders, and light construction equipment often ship on step-decks.
Capacity: Typically 48,000 lbs payload. Deck length usually 48–53 feet on the lower section.
Loading: Ramps are used to drive equipment onto the rear deck. The machine must be operational or a forklift must be available.
Permit threshold: If the combined height (trailer deck + equipment) stays under 13.5 feet, no height permit is needed. Width over 8.5 feet still triggers an oversize permit.
Lowboy Trailers
A lowboy (also called a double-drop or float) has a very low center section — typically 18–24 inches off the ground — that provides maximum vertical clearance for tall machinery. The deck drops down behind the gooseneck and rises again at the rear for the wheels.
Best for: Mid-size to large equipment that's too tall for a step-deck. Motor graders, large excavators, crawler dozers, and compactors commonly ship on lowboys.
Capacity: Standard two-axle lowboys handle 40,000–80,000 lbs. Multi-axle configurations can exceed 150,000 lbs.
Loading: Standard lowboys have a fixed neck, so loading requires ramps or a crane. The machine must be driven up ramps or lifted onto the deck.
Deck length: Typically 24–29 feet in the well section.
RGN (Removable Gooseneck) Trailers
An RGN is a lowboy with one critical difference: the front gooseneck section detaches hydraulically, allowing the deck to drop all the way to the ground. This creates a gentle slope that self-propelled equipment can drive directly onto — no ramps, no crane needed.
Best for: Any self-propelled equipment that needs ground-level loading. Excavators, dozers, motor graders, and wheel loaders are almost always shipped on RGNs when they're operational.
Capacity: Standard RGNs handle 40,000–80,000 lbs. Multi-axle "stretch" RGNs can carry 150,000+ lbs for superloads.
Deck length: 29–53 feet standard; stretch configurations available for very long loads.
Cost: RGNs command a premium over standard lowboys — typically 10–20% higher per-mile rates — due to their hydraulic complexity and higher tare weight. But they save money on loading costs when crane or forklift rental would otherwise be required.
Quick Decision Guide
| Situation | Best Trailer |
|---|---|
| Equipment under 48,000 lbs, under 13 ft tall | Step-Deck |
| Equipment 40,000–80,000 lbs, crane available for loading | Lowboy |
| Self-propelled equipment, no crane on-site | RGN |
| Equipment over 80,000 lbs, very long or wide | Multi-axle RGN or specialized lowboy |
| Non-operational equipment, crane available | Lowboy (most cost-effective) |
What IronHaul Recommends
When in doubt, go with an RGN. The ground-level loading capability eliminates the need for on-site loading equipment, reduces the risk of damage during loading, and speeds up the process at both pickup and delivery. The modest rate premium is almost always worth it for equipment over 30,000 lbs.
Have questions about which trailer your specific machine needs? IronHaul's dispatch team can advise based on your equipment's make, model, and dimensions. Call (208) 495-2260, email [email protected], or submit a quote request online and we'll recommend the right solution.
Common questions
What is the difference between an RGN and a lowboy trailer?
Both are low-deck trailers designed for tall, heavy equipment. The key difference is that an RGN has a detachable front gooseneck that drops the deck to ground level for drive-on loading. A standard lowboy has a fixed neck and requires ramps or a crane for loading.
Can a step-deck handle an excavator?
A step-deck can handle compact excavators (under ~22,000 lbs) that fit within height limits. Mid-size and large excavators typically require a lowboy or RGN due to their height and weight.
Is an RGN more expensive than a lowboy?
Yes, RGN trailers typically cost 10–20% more per mile than standard lowboys due to their hydraulic detach mechanism and higher tare weight. However, they eliminate crane or forklift loading costs, which can offset the difference.
What is the maximum weight a lowboy can carry?
Standard two-axle lowboys handle 40,000–80,000 lbs. Multi-axle configurations can carry 150,000 lbs or more for superload moves.
Do I need a permit for a step-deck shipment?
If the combined height of the trailer and equipment stays under 13.5 feet and the width is under 8.5 feet, no permit is needed. Exceeding either threshold triggers state oversize permit requirements.
Ready to move a machine?
Tell us what you're shipping and where. We quote direct — no bidding wars, no load-board runaround.