Flatbed Trailer Dimensions and Legal Load Limits: 48 vs 53 Foot Guide
A standard flatbed trailer is 48 or 53 feet long and 102 inches wide, with a deck about 5 feet off the ground. That leaves room for freight up to about 8 feet 6 inches tall and 46,000 to 48,000 pounds before a load needs a permit. Knowing flatbed trailer dimensions and legal load limits tells you whether your freight moves as a standard load or needs special equipment.
This guide covers flatbed, step deck, double drop, RGN and Conestoga specs, weight limits, securement rules and when you need an oversize permit. It is written by MigWay, an asset-based carrier in Pineville, North Carolina, running 400 trucks and 750 trailers across dry van and flatbed.
What are standard flatbed trailer dimensions?
Standard flatbed trailers come in 48-foot and 53-foot lengths, both 102 inches wide. The deck sits about 60 inches off the ground, roughly the same height as a loading dock.
| Measurement | 48-foot flatbed | 53-foot flatbed |
|---|---|---|
| Deck length | 48 ft | 53 ft |
| Deck width | 102 in (8 ft 6 in) | 102 in (8 ft 6 in) |
| Deck height | about 60 in (5 ft) | about 60 in (5 ft) |
| Max legal freight height | about 8 ft 6 in | about 8 ft 6 in |
| Typical max payload | 46,000 to 48,000 lbs | 45,000 to 47,000 lbs |
How legal freight height is figured
Most eastern states cap total height at 13 feet 6 inches, including North Carolina, South Carolina, Virginia and the Northeast. Subtract the 5-foot deck and you get about 8 feet 6 inches of legal freight height. Some western states allow 14 feet, which adds 6 inches. Always plan for the lowest limit on your route.
Should you ship on a 48-foot or 53-foot flatbed?
Use a 48-foot flatbed for heavy, concentrated freight and a 53-foot flatbed for long or light freight that needs deck space. The 48-foot flatbed is the most common size in the U.S. fleet.
- 48-foot flatbed: weighs a little less, turns tighter on job sites, and meets kingpin rules in every state, including California's 40-foot kingpin-to-rear-axle limit when set up properly.
- 53-foot flatbed: adds 5 feet of deck for long materials like pipe, lumber bundles or trusses, or for loads with many small pieces.
- Spread axle trailers: many flatbeds have rear axles about 10 feet apart instead of a closed tandem. In many states, that raises the trailer axle limit from 34,000 pounds to up to 40,000 pounds, helping with heavy steel or machinery.
If your freight is under 48 feet long, a 48-foot trailer usually gives the best mix of payload and access. Tell your carrier the piece count, length and weight of the heaviest item, and they will pick the right setup.
What are the dimensions of step deck, RGN and Conestoga trailers?
When freight is too tall for a flatbed, a lower deck buys more legal height. When freight needs protection from weather, a Conestoga adds a rolling tarp system. Here is how the main open-deck trailers compare.
| Trailer type | Main deck length | Main deck height | Max legal freight height | Typical max payload |
|---|---|---|---|---|
| Flatbed | 48 to 53 ft | about 5 ft | about 8 ft 6 in | 46,000 to 48,000 lbs |
| Step deck (single drop) | 38 to 41 ft lower deck | 3 ft 4 in to 3 ft 6 in | about 10 ft 2 in on the lower deck | 44,000 to 47,000 lbs |
| Double drop | 24 to 29 ft well | 1 ft 6 in to 2 ft | about 11 ft 6 in in the well | 37,000 to 40,000 lbs |
| RGN (removable gooseneck) | 24 to 29 ft well | 1 ft 6 in to 2 ft | about 11 ft 6 in in the well | 37,000 to 40,000 lbs |
| Conestoga | 48 to 53 ft | about 5 ft | about 8 ft to 8 ft 2 in (inside the tarp frame) | 44,000 to 46,500 lbs |
Specs from C.H. Robinson's flatbed equipment guide; actual numbers vary by manufacturer. An RGN's front detaches so equipment can drive on, which makes it the go-to for tracked machinery. Learn more in our guide to Conestoga trailers.
How much weight can a flatbed trailer carry?
A standard five-axle flatbed can legally carry about 46,000 to 48,000 pounds. Flatbed trailers weigh less than dry vans, especially aluminum or combo models, so they can usually haul a few thousand pounds more.
Axle limits on a flatbed
- Gross vehicle weight: 80,000 lbs on the Interstate system
- Steer axle: about 12,000 lbs in practice
- Drive tandem: up to 34,000 lbs
- Trailer tandem: up to 34,000 lbs, or up to 40,000 lbs on a spread axle in many states
Placement matters more on flatbeds than vans. A single steel coil or machine puts all its weight on a small section of deck. Carriers position heavy pieces so each axle group stays legal and the deck is not overloaded at one point. Tell your carrier the weight and footprint of the heaviest piece when you book.
Loads over 80,000 pounds gross, or over axle limits, need an overweight permit and usually specialized equipment.
What are the flatbed load securement rules?
Flatbed securement is governed by federal rules in 49 CFR Part 393, Subpart I. Two rules decide how many straps or chains a load needs.
Rule 1: Working load limit
The combined working load limit of all tiedowns must equal at least half the weight of the cargo. A 40,000-pound load needs tiedowns rated for at least 20,000 pounds combined.
Rule 2: Minimum number of tiedowns
| Article size (not blocked in front) | Minimum tiedowns |
|---|---|
| 5 ft or shorter and 1,100 lbs or less | 1 |
| 5 ft or shorter and over 1,100 lbs | 2 |
| Over 5 ft, up to 10 ft | 2 |
| Over 10 ft | 2, plus 1 for every additional 10 ft or fraction |
Both rules apply, and the load must meet whichever requires more. Specific commodities, such as steel coils, lumber, concrete pipe and heavy machinery, have extra rules. Our driver guide to flatbed load securement covers them in detail.
For shippers, the practical point is simple: have freight banded, blocked and palletized where possible, and leave room for the driver to strap it. Loose or unbanded bundles slow loading and raise damage risk.
When does a flatbed load need an oversize permit?
A flatbed load generally needs a state permit when it goes over any standard legal limit. Each state on the route issues its own permit, with its own rules.
| Limit | Standard legal maximum | What happens above it |
|---|---|---|
| Width | 8 ft 6 in (102 in) | Oversize permit, "Oversize Load" banners, flags; escorts at wider widths set by each state |
| Height | 13 ft 6 in total in most eastern states | Oversize permit and a route survey for bridges and power lines on taller loads |
| Gross weight | 80,000 lbs | Overweight permit and often extra axles |
| Rear or side overhang | Varies by state | Red or orange flags at least 12 inches square on loads extending 4 ft or more past the rear, and on side projections |
How the permit process works
- The shipper provides exact dimensions and weight of the load.
- The carrier picks equipment that keeps the load as close to legal as possible.
- The carrier applies for permits in every state on the route, such as through NCDOT's Oversize/Overweight Permit Unit in North Carolina.
- The state sets the approved route, travel hours and any escort requirements.
- The load moves under those terms, often in daylight hours only and with weekend or holiday limits in many states.
Permits take time. Give your carrier accurate measurements early, because a wrong number can void a permit at a weigh station.
When does flatbed freight need to be tarped?
Freight that can be damaged by rain, road grime or sun needs a tarp. Common examples include drywall, finished lumber, steel that must not rust, insulation and packaged building products.
- Lumber tarps: larger tarps with long drops for tall loads like lumber and building materials.
- Steel tarps: smaller tarps with shorter drops for lower, heavier loads.
- Smoke tarps: cover the front of a load to shield it from exhaust.
- Conestoga: a rolling tarp system that removes the need for manual tarping on sensitive freight.
Tell your carrier at booking if the load needs tarps and what kind. Tarping adds time at pickup, so it affects scheduling.
How does MigWay handle flatbed freight?
MigWay runs a flatbed division out of Pineville, North Carolina, serving construction, steel and industrial shippers across 48 states. Every load moves on our own trucks with our own drivers.
- Asset fleet: 400 trucks and 750 trailers across flatbed and dry van.
- Common freight: steel coil and structural steel, lumber and building materials, machinery, precast and HVAC equipment.
- Tarping and securement: drivers trained on commodity-specific securement and tarping.
- Experienced drivers: at least two years of recent OTR experience required.
- 24/7 in-house dispatch and ELD and GPS tracking on every load.
- Flat, all-in pricing: one rate with fuel and standard charges included.
Not sure if your load fits a standard flatbed? Send us the dimensions and weight of your largest piece. Request a freight quote or start a chat with our team, or call +1-980-255-3200.
What are the key flatbed trailer dimensions and legal load limits?
For most shipments, remember these flatbed trailer dimensions and legal load limits: 48 or 53 feet long, 102 inches wide, a 5-foot deck, about 8 feet 6 inches of legal freight height and 46,000 to 48,000 pounds of payload. Taller freight moves on a step deck or RGN, and anything wider than 8 feet 6 inches or heavier than 80,000 pounds gross needs permits. For dry van specs, see our 53-foot dry van dimensions guide.
Frequently Asked Questions
What are the dimensions of a standard flatbed trailer?
A standard flatbed is 48 or 53 feet long and 102 inches wide, with a deck about 5 feet off the ground. It can carry freight up to about 8 feet 6 inches tall in most states without a permit.
How much weight can a flatbed carry?
A standard five-axle flatbed can legally carry about 46,000 to 48,000 pounds. The limit is the 80,000-pound gross weight cap minus the weight of the truck and trailer, plus axle limits along the way.
How tall can freight be on a flatbed?
About 8 feet 6 inches in most eastern states, where total height is capped at 13 feet 6 inches. Taller freight needs a step deck, double drop or RGN, or an oversize permit.
How wide can a flatbed load be without a permit?
Up to 8 feet 6 inches, or 102 inches. Anything wider needs an oversize permit in each state on the route, plus banners and flags, and escorts at larger widths.
What is the difference between a flatbed and a step deck?
A step deck has a lower main deck, about 3 feet 4 inches to 3 feet 6 inches off the ground, behind a short upper deck. That allows freight up to about 10 feet tall without a permit, compared to about 8 feet 6 inches on a flatbed.
Is a 48-foot or 53-foot flatbed more common?
The 48-foot flatbed is more common. It weighs less, maneuvers better on job sites and meets kingpin rules in every state. A 53-foot flatbed is used for long freight or loads that need extra deck space.
What is a spread axle flatbed?
A spread axle flatbed has its rear axles about 10 feet apart instead of close together. In many states, this allows up to 40,000 pounds on the trailer axles instead of 34,000, which helps with heavy, concentrated loads.
How many straps does a flatbed load need?
Federal rules require tiedowns with a combined working load limit of at least half the cargo weight. Articles over 10 feet need at least two tiedowns plus one for each additional 10 feet. Some commodities have extra rules.
When do flatbed loads need flags?
Federal rules require red or orange flags at least 12 inches square on loads that extend 4 feet or more past the rear of the trailer. Flags also mark side projections and oversize loads.
Does MigWay haul flatbed freight?
Yes. MigWay runs a flatbed division from Pineville, North Carolina, hauling steel, lumber, building materials and machinery across 48 states. Our fleet includes 400 trucks and 750 trailers.