RGN vs. Lowboy vs. Step Deck: How to Choose the Right Trailer for Your Equipment
One of the most common questions equipment shippers ask is: which trailer do I need? The answer depends on your equipment's weight, height, and how it needs to be loaded. Choosing the wrong trailer can mean a rejected load at the auction yard, a permit violation on the highway, or damage to your equipment during loading. This guide breaks down the real differences between RGN, lowboy, and step deck trailers so you can make the right call—or at least have an informed conversation with your carrier.
The Core Problem: Height
The fundamental reason heavy equipment requires specialized trailers is height. Federal and state regulations limit the combined height of the truck, trailer, and load to 13 ft 6 in on most highways (some states allow 14 ft). A standard flatbed trailer deck sits 48–60 inches off the ground. Add a 10-foot-tall excavator, and you're at 18–20 feet—well over the legal limit. Specialized trailers solve this by lowering the deck height, keeping the combined load height within legal limits or at least minimizing the permit tier required.
Step Deck (Drop Deck) Trailers
A step deck trailer has two deck levels: a higher front section (typically 48–54 inches off the ground) and a lower rear section (typically 34–42 inches off the ground). The step down occurs behind the tractor's rear axles.
Best for:
- Forklifts and telehandlers (mast height is the critical measurement)
- Skid steers and compact track loaders
- Light to mid-weight equipment (up to 48,000 lbs)
- Equipment that can be driven or rolled onto the trailer via ramps
- Loads that are within legal width (under 8 ft 6 in) but slightly tall
Limitations:
- The lower deck section is still 34–42 inches off the ground—not low enough for tall tracked equipment like large excavators or dozers
- Weight capacity is typically limited to 48,000 lbs on the lower deck
- Loading requires ramps, which can be challenging for heavy tracked equipment
Lowboy Trailers
A lowboy trailer has a very low deck height—typically 18–24 inches off the ground in the main well section. This is achieved by dropping the deck between the front and rear axle groups. The low deck height is the key advantage: it allows tall equipment to be transported while keeping the combined load height within or near legal limits.
Best for:
- Mid-size to large excavators (20–50 tons)
- Crawler dozers and track loaders
- Motor graders and compactors
- Equipment that can be loaded via ramps at the rear
- Loads up to 80,000 lbs (standard lowboy)
Limitations:
- Fixed gooseneck means equipment must be loaded via rear ramps—not ideal for very heavy machines that are difficult to drive up a ramp
- The ramp angle can be steep for very heavy tracked equipment, creating loading challenges
- Standard lowboys are limited to approximately 80,000 lbs; heavier loads require multi-axle configurations
RGN (Removable Gooseneck) Trailers
An RGN trailer has a detachable front section (the gooseneck) that allows the front of the trailer to be lowered to the ground, creating a ramp. Equipment drives directly onto the trailer from the front—no rear ramps required. The deck height in the main well is similar to a lowboy (18–22 inches), but the drive-on loading capability makes RGNs far more versatile for heavy, tall, or difficult-to-maneuver equipment.
Best for:
- Large excavators (40+ tons) that are difficult to drive up rear ramps
- Wheel loaders and motor graders with high bucket/blade profiles
- Concrete pump trucks and other wheeled equipment that can drive on
- Very heavy loads (up to 150,000+ lbs with multi-axle configurations)
- Equipment with low ground clearance that cannot navigate steep rear ramps
Limitations:
- RGNs are more expensive to rent/operate than standard lowboys
- The drive-on loading process requires more space at the pickup location
- Not all carriers have RGN capacity—availability can be tighter than lowboys
Quick Reference: Which Trailer for Which Equipment
| Equipment | Recommended Trailer | Why |
|---|---|---|
| Mini excavator (under 10 tons) | Step Deck or Flatbed | Light enough; height usually within limits on step deck |
| Mid-size excavator (10–30 tons) | Lowboy | Low deck keeps combined height manageable; rear ramp loading works |
| Large excavator (30–50+ tons) | RGN | Drive-on loading safer for heavy machines; low deck for height |
| Crawler dozer (D6–D11 class) | Lowboy or RGN | Wide blade may require oversize permit; RGN for largest dozers |
| Wheel loader (mid to large) | RGN | Bucket height pushes combined height over 14 ft on flatbed or step deck |
| Forklift (under 30,000 lbs) | Step Deck | Mast height is the concern; step deck provides adequate clearance |
| Telehandler | Step Deck or Lowboy | Depends on boom height in transport position |
| Skid Steer / CTL | Flatbed or Step Deck | Usually within legal limits; multiple units on one trailer |
| Motor Grader | Lowboy or RGN | Blade width often triggers oversize permit; low deck for height |
| Asphalt Paver | RGN or Lowboy | Width is primary concern; drive-on loading preferred for large pavers |
When Your Carrier Recommends a Different Trailer
Sometimes a carrier will recommend a different trailer than you expect. This usually happens because of specific route constraints (a bridge with a low weight limit that requires more axles), equipment dimensions that don't match the standard recommendation, or trailer availability in your area. A good carrier will explain the reasoning—if they can't, that's a red flag.
Not sure which trailer your equipment needs? IronHaul Logistics will assess your equipment's dimensions and weight and recommend the right trailer for your specific move. Call (208) 495-2260, email [email protected], or submit a quote request online. We'll have a recommendation and rate back to you within hours.
Common questions
What is the main difference between an RGN and a lowboy trailer?
Both have similar low deck heights (18–24 inches), but an RGN has a removable front gooseneck that allows equipment to drive directly onto the trailer from the front. A lowboy has a fixed gooseneck and requires equipment to be loaded via rear ramps. RGNs are preferred for very heavy or difficult-to-maneuver equipment; lowboys are more widely available and cost-effective for standard loads.
Can a step deck trailer carry an excavator?
A step deck can carry a mini excavator (under 10 tons) if the combined height stays within legal limits. For mid-size and large excavators, a lowboy or RGN is required because the step deck's lower deck section (34–42 inches) is still too high—the combined load height would exceed legal limits.
What is the weight limit for a standard lowboy trailer?
A standard lowboy trailer typically has a weight capacity of approximately 80,000 lbs. For heavier loads, multi-axle lowboy configurations or RGN trailers with additional axles can handle up to 150,000+ lbs, though these require overweight permits and careful axle weight distribution.
Why is an RGN preferred for large wheel loaders?
Large wheel loaders have tall bucket profiles that push the combined load height over 14 feet on a flatbed or step deck. An RGN's low deck height (18–22 inches) minimizes the combined height, and the drive-on loading capability allows the loader to drive directly onto the trailer without navigating steep rear ramps.
How do I know if my equipment needs a lowboy or an RGN?
The key factors are weight and loading method. If your equipment weighs over 80,000 lbs or is difficult to drive up rear ramps (due to weight, low ground clearance, or size), an RGN is usually the better choice. For equipment under 80,000 lbs that can be loaded via rear ramps, a lowboy is typically more cost-effective and widely available. Contact IronHaul with your equipment specs and we'll recommend the right trailer.
Ready to move a machine?
Tell us what you're shipping and where. We quote direct — no bidding wars, no load-board runaround.