Trailer selection
Flatbed vs Step-Deck vs RGN: Which Trailer Does Your Load Need?
Cargo up to 8 feet 6 inches tall rides on a flatbed. Up to 10 feet rides on a step-deck. Anything taller, or most tracked heavy machinery, needs an RGN. Cost climbs with each step: step-deck runs 15 to 25 percent above flatbed, RGN runs 40 to 50 percent above flatbed on the same lane.
As of July 2026. These ranges come from real heavy-haul loads brokered by AIG Enterprises, licensed freight broker MC 931605.
Our curve prices each trailer with a consistent multiplier over the flatbed baseline on the same corridor and distance band. The Rate Desk picks the smallest trailer your load rides legally on.
The decision, in one sentence per trailer
- Flatbed: deck 5 feet off the ground, so cargo up to 8 feet 6 inches tall stays under the 13-foot-6 federal ceiling. Cheapest to book. Great for steel, lumber, machinery under 8 feet tall, palletized building materials.
- Step-deck (also called drop-deck): deck steps down to about 3 feet 6 inches, so cargo up to 10 feet tall stays legal. Same width and weight rules as flatbed. Good for medium-sized machinery, containers, coils that sit tall.
- RGN (removable gooseneck, also called lowboy): deck sits 18 to 22 inches off the ground, so cargo up to 11 feet 6 inches or more stays legal, and heavy machinery can drive on and off. Required for most tracked excavators, dozers, wheel loaders, cranes, and any oversize industrial piece.
Comparison table
| Spec | Flatbed | Step-deck | RGN |
|---|---|---|---|
| Deck height | ~ 5 ft | ~ 3 ft 6 in (lower deck) | ~ 18 to 22 in |
| Max legal cargo height | 8 ft 6 in | 10 ft | 11 ft 6 in + |
| Typical deck length | 48 or 53 ft | 48 ft (37 lower + 11 upper) | 28 to 53 ft with extensions |
| Typical payload | 48,000 lbs | 44,000 lbs | 40,000 to 150,000+ lbs (multi-axle) |
| Cost vs flatbed baseline | Baseline | +15 to 25% | +40 to 50% |
| Best for | Steel, lumber, small equipment | Mid-size machinery, wrapped equipment | Tracked excavators, dozers, cranes |
Real-world examples
- 20 tons of coil steel, Pittsburgh to Nashville: flatbed. Coils are heavy but short, so the deck height does not matter and the truck is easy to find.
- Wrapped conveyor assembly 9 feet 6 inches tall, Chicago to Dallas: step-deck. On a flatbed the load would be over-height and require permits. On a step-deck it stays legal.
- Cat 336 tracked excavator, Denver to Phoenix: RGN, permitted. Even on the low deck the boom stack pushes the load into over-height and over-width in AZ. RGN plus a permit set in both states.
- Bobcat T650 compact track loader, Atlanta to Charlotte: flatbed. Under 10,000 pounds, under 7 feet tall. No permits, cheap and fast.
The cost relationship
Across the same lane and same distance band, our curve prices the three trailers with a consistent multiplier. Step-deck runs roughly 15 to 25 percent above flatbed. RGN runs roughly 40 to 50 percent above flatbed. That gap is why picking the smallest trailer your load will legally ride on is the single biggest lever on the final number.
Do not over-trailer a load to be safe. If a mid-size excavator fits on a step-deck, quoting it as an RGN out of caution costs the shipper real money. That is why the Rate Desk runs multiple trailer scenarios on borderline units and offers you the cheaper legal option.
Not sure which trailer you need? Tell the Rate Desk what you are shipping. It picks the trailer, prices the move, and shows you the math.