Lowboy Trailer Dimensions: Well Length, Deck Height & Weight Limits
Accurate dimensions are critical for planning lowboy loads. A miscalculation of even a few inches can mean the difference between a legal load and one that requires oversize permits. This guide covers every specification you need — deck height, well length, width, overall length, tare weight, and payload capacity — broken down by axle configuration and gooseneck type.
18-24"
Deck Height
24-53 ft
Well Length Range
8'6"
Standard Width
15K-26K lbs
Tare Weight Range
O Trucking Editorial Team
Trucking Industry Experts
Fact-Checked by O Trucking Dispatch Team
5+ years coordinating heavy haul loads, verifying trailer specifications, and managing oversize permit logistics
This article was written by the O Trucking editorial team with 9+ years of combined trucking industry experience. Learn more about us.
O TruckingLowboy Trailer Dimensions: Well Length, Deck Height & Weight Limits (2026)
Lowboy Trailer Dimensions Overview
Every lowboy trailer dimension serves a specific purpose in heavy haul transport. The deck height determines how tall your cargo can be. The well length determines how long your equipment can be. The width determines whether you need overwide permits. And the tare weight determines how much payload capacity you actually have.
| Dimension | FGN Lowboy | RGN Lowboy | Why It Matters |
|---|---|---|---|
| Deck Height | 18-24" | 18-24" | Determines max cargo height under 13'6" limit |
| Well Length | 24-29 ft | 29-53 ft | Usable flat deck for equipment placement |
| Overall Width | 8'6" | 8'6" | Legal maximum without overwide permit |
| Overall Length | 48-53 ft | 48-53 ft | Gooseneck to rear bumper total length |
| Tare Weight | 15,000-20,000 lbs | 18,000-26,000 lbs | Reduces net payload from gross capacity |
| Ground Clearance | 6-10" | 6-10" | Clearance under lowest point of deck |
Deck Height: 18 to 24 Inches
The deck height of a lowboy trailer — the distance from the ground to the top of the deck surface in the well section — ranges from 18 to 24 inches. This is the lowest deck height of any trailer type and is the primary reason lowboys exist.
With a federal overall height limit of 13'6" in most states (some states allow 14'0" on specific highways), the deck height directly determines your maximum cargo height:
- 18-inch deck — Maximum cargo height of approximately 11'10" (13'6" minus 20" for deck plus equipment securing)
- 20-inch deck — Maximum cargo height of approximately 11'6"
- 22-inch deck — Maximum cargo height of approximately 11'4"
- 24-inch deck — Maximum cargo height of approximately 11'2"
The exact deck height varies by manufacturer, model year, tire size, and load. A lowboy's air ride suspension compresses under heavy loads, which can actually lower the deck height by 1 to 2 inches when loaded. Conversely, an unloaded lowboy sits slightly higher. Always measure the deck height under loaded conditions for the most accurate height calculation.
Account for Equipment Securement Height
Well Length: 24 to 53 Feet
The well length is the length of the flat, recessed deck section where equipment actually sits. This is the usable deck space — and it is significantly shorter than the trailer's overall length because the gooseneck and rear axle risers consume deck length.
Well length varies dramatically between FGN and RGN lowboys:
Fixed Gooseneck (FGN): 24-29 ft Well
FGN lowboys have shorter wells because the fixed gooseneck takes up more of the trailer's overall length. A typical 48-foot FGN trailer has a well of about 24 to 26 feet. Longer models (53 feet) may have wells up to 29 feet. This is sufficient for most single pieces of equipment (excavators, bulldozers, wheel loaders) but limits your options for longer equipment or multiple pieces on one trailer.
Removable Gooseneck (RGN): 29-53 ft Well
RGN lowboys offer significantly longer wells because the detachable gooseneck can be designed to consume less deck space. Standard RGN models have 29 to 35 foot wells. Extended or stretch RGN trailers can offer wells up to 53 feet, making them suitable for very long equipment like bridge beams, wind turbine components, and large industrial structures. For more on RGN specifications, see our lowboy vs RGN guide.
Measure Usable Flat Deck, Not Total Well Length
Width & Overall Length
Standard lowboy trailer width is 8 feet 6 inches (102 inches), which is the maximum legal width for non-permitted loads on US highways. Some specialized lowboys are built wider (up to 10 feet or more) for hauling wide equipment, but these require overwide permits on every trip.
Many lowboy loads exceed the trailer's width because the equipment itself is wider than 8'6". Excavators, for example, often have tracks that extend 9 to 11 feet wide. When equipment overhangs the sides of the trailer, the overall load width is what matters for permit purposes — not the trailer width.
Overall trailer length ranges from 48 to 53 feet from gooseneck to rear bumper. Combined with a typical tractor, the total vehicle length (tractor + trailer) runs about 65 to 75 feet. Most states allow up to 75 feet total combination length without an overlength permit, but some states have shorter limits on certain roads.
Specifications by Axle Configuration
The number of axles on a lowboy trailer determines its weight capacity, tare weight, and overall length. Here is how the specs break down by axle count:
| Spec | 2-Axle | 3-Axle | 4+ Axle |
|---|---|---|---|
| Payload Capacity | ~40,000 lbs | ~60,000 lbs | ~80,000+ lbs |
| Tare Weight | 15,000-18,000 lbs | 18,000-22,000 lbs | 22,000-28,000 lbs |
| Deck Height | 18-22" | 20-24" | 22-26" |
| Well Length (typical) | 24-28 ft | 24-30 ft | 26-35 ft |
| Overall Length | 48-50 ft | 48-53 ft | 50-65 ft |
| Best For | Mid-size equipment, skid steers | Large excavators, bulldozers | Crawler cranes, mining equipment |
Tare Weight & Its Impact on Payload
Tare weight — the weight of the trailer itself when empty — directly reduces your available payload capacity. A heavier trailer means less weight available for cargo before hitting the gross vehicle weight limit.
Consider a typical setup with an 80,000-pound GVW limit: a tractor weighing 18,000 pounds plus a 3-axle RGN lowboy weighing 22,000 pounds uses 40,000 pounds before you load a single piece of equipment. That leaves 40,000 pounds of payload capacity. If you used a lighter 2-axle FGN (15,000 pounds tare), you would have 47,000 pounds of payload — but you would also have less axle capacity for distributing that weight legally.
RGN trailers are heavier than FGN trailers because the removable gooseneck mechanism adds 3,000 to 6,000 pounds. This is a trade-off: the RGN gains loading flexibility but loses payload capacity. For loads near the GVW limit, those extra pounds matter. See our weight capacity guide for detailed calculations.
FGN vs RGN: Dimension Differences
The gooseneck type affects several key dimensions beyond just the loading method:
Well length — RGN trailers offer 5 to 24 feet more usable deck space than comparable FGN models. This is the biggest dimensional advantage of the RGN design.
Tare weight — RGN trailers weigh 3,000 to 6,000 pounds more than comparable FGN models due to the hydraulic or mechanical detach mechanism and reinforced gooseneck connection.
Deck height — Both types offer similar deck heights (18-24 inches). RGN models are occasionally 1-2 inches higher due to the additional structural material needed for the detach mechanism.
Ground clearance when detached — RGN trailers sit with their front end on the ground when the gooseneck is removed. The loading angle depends on the deck height and distance from the ground — typically creating a 5 to 8 degree ramp angle.
How to Measure Your Lowboy Before Loading
Never rely solely on manufacturer specs or advertised dimensions. Always measure the actual trailer you are loading. Here are the critical measurements to take:
Deck Height (Loaded)
Measure from the ground to the top of the deck surface in the center of the well. Do this measurement when the trailer is loaded (or at the expected load weight) because air ride suspension compresses 1 to 2 inches under load. This is your actual deck height for height calculations.
Usable Flat Deck Length
Measure the distance between where the deck transitions from the gooseneck slope to flat and where it transitions from flat to the rear axle riser. This is your true usable deck length — not the advertised well length. It is typically 2 to 4 feet shorter than the marketed spec.
Inside Width Between Stake Pockets
Measure the inside width of the deck between the inner edges of the stake pockets or rub rails. This is the actual space your equipment must fit within — not the outer width of the trailer. Equipment that is exactly 8'6" wide may not fit between stake pockets that reduce the usable width to 8'2".
Tie-Down Point Locations
Map the location and capacity of every tie-down point (D-rings, recessed hooks, stake pockets) on the trailer. You need tie-downs positioned to secure equipment against forward, rearward, and lateral movement. If tie-down points do not align with your equipment's securement points, you may need additional blocking or rigging.
Manufacturer Spec Sheets Are Your Starting Point
How Our Team Uses Dimension Data
At O Trucking LLC, we verify trailer dimensions against equipment specs on every heavy haul load before booking. Our dispatchers confirm deck height, usable well length, and width clearance to ensure the load is both legal and safe. We do not book loads based on assumptions — we confirm the numbers.
For more on lowboy trailer types and choosing between FGN and RGN, see our types of lowboy trailers guide and our lowboy trailer glossary page.
Continue Reading
Need Help Planning a Heavy Haul Load?
Our dispatch team verifies trailer dimensions, calculates load heights, and coordinates permits for every lowboy shipment. Let us handle the logistics.