A step deck trailer is a common open deck trailer that is versatile in it's capabilities. A step deck, or commonly referred to as a drop deck is able to carry a broad range of both legal commodities and oversize shipments. This article gets into the specifics of the step deck trailer. A general discussion of the trailer capabilities, trailer dimensions, commodity dimensions, axle groups and weights, and accessories that make it an effective trailer type for the open deck market. Any pros and cons are discussed on the different trailer specs.
Types of Trailers & DimensionsA Note About Dimensions
Dimensions can vary on trailers and state regulations. Be sure you understand the state requirements and trailer before hauling any load. DO NOT use any dimensions listed below as they are intended as averages and for general industry understanding.
Step Deck
Commodity Hauling
A step deck can haul a broad range of freight, from palletized goods to machinery. Open deck trailers have a key advantage over van trailers, or enclosed trailers, because a step deck allows loading from the side or overhead with a crane.
Step Deck Dimensions
As with most trailer types the dimensions can vary both on the actually trailer dimensions and the commodity dimensions.
Step Deck Length
The primary advantage of a stepdeck is the lower deck height allows for taller pieces and still be legal. The sacrifice a stepdeck makes for this advantage is typically less commodity weight and less deck space to haul longer items.
There are several dimensions to consider when talking length on a step deck trailer.
- Overall Length - The overall length is between 48' and 53'. Many driver's are opting for 53' trailers as they can have more lower deck space available.
- Lower Deck Length - The lower deck, or bottom deck, ranges between 37' - 41' typically.
- Upper Deck Length - The upper deck, or top deck, ranges between 10' - 12'.
- Commodity Length - Because step deck trailers are so versatile on the commodities they can haul, you will see all versions of product on the upper deck, lower deck, overhang off the upper deck and overhang off the rear deck.
- Overlength Loads - Overlength permitted loads generally refer to rear overhang off the trailer. The amount of legal overhang varies among states before a permit is required. Some states allow for 3' overhang on 48' trailers and no overhang on 53' trailers.
Step Deck Width
The width is fairly straight forward. Most open deck trailers are 8'6" (102") wide. This is the legal limit for commodity width as well, so it's one of the first dimensions to know and understand in the trucking industry.
- Trailer Width - Most open deck trailers are 8'6" (102"). Often the deck width is referred to as a "102" referring to the 102 inches dimension.
- Legal Commodity Width - The max legal commodity dimension is 8'6" (102"). Any load exceeding this limit is considered oversize and would require state permit.
- Overwidth Loads - If the commodity is over 8'6", a state oversize permit is going to be required. If the load gets too wide, about 12' wide or greater, then an oversize escort will be required as well. This is dependent on many factors.
Step Deck Height
There are several height dimensions to keep in mind when talking about a step deck trailer. It's important to discuss the actual commodity height when determining what is necessary in hauling, as the trailer dimensions can vary between trailers.
- Deck Height - This typically refers to the height of the lower deck from the ground to the top of the lower deck. Because these deck heights can vary, it's very important to know the exact commodity height to be sure the equipment hauling can load it legally.
- 3'6" (42") - Standard deck height.
- 3' (36") - Low profile step deck height
- Step or Drop Height - The step, or drop, of the trailer is the transition height from the upper deck (at the front) to the lower deck. This step is about 1'6" - 1'9" high.
- Commodity Height - The advantage of a step deck over a flatbed trailer is that the commodity height of a step deck can legally haul heights of 10' and sometimes more depending the trailer.
- Oversize Height - Step decks can haul commodities that exceed 10' but the load will require an oversize permit and in some cases a pole car or height escort will be required. Over height loads cost more to haul due to the specialized nature of the load, the state permits required, and any additional escort fees that may also be required.
Tandem vs Spread Axle Groups
The difference between the two is mostly all about weight. Most 5 axle semi tractor trailer combinations use a trailer set up with a trailer tandem axle configuration. Step decks you will find use both methods.
Either trailer setup cannot exceed the 80,000 lbs gross weight limit.
Tandem Axle
This is the traditional trailer axle group and allows for 17,000 lbs per axle or 34,000 per tandem group.
Pros
- Tandem axles can move forward or backward to adjust loaded weight.
- Slower tire wear.
- More maneuverable.
Spread Axle
A spread axle is splitting the tandem axle group to a distance of 10'. Each axle is treated as a single axle group which has a weight limit of 20,000 lbs. In this combination the spread axle can handle 40,000 lbs.
Pros
- More forgiving on loaded weight distribution.
- Smoother ride.
Cons
- Some state and province restrictions.
Accessories
There are many step deck accessories that can make a step deck trailer more versatile given the customer and driver more capabilities. Some accessories are value added in that there are additional costs on the load. Tarping is an excellent example of an accessorial that requires more expense. Some of the accessories listed below are not equipment oriented, an accessorial could also be truck or driver provided, meaning a driver or truck has a license or expertise that not all drivers or trucks have and, therefore, provide a value add.
- Tarps - Open deck trailers, including step decks, haul commodities that are open to the weather, road debris, and wind (highway speeds too). A tarp can can help protect the commodity, but they aren't fool proof either. Tarps can rip or have holes and if a customer has sensitive commodities then further protection is required like crates, etc.
- Ramps - Ramps allow for vehicles to be driven on the rear trailer or ramped up to the upper deck as well. Not all ramps can support the same weight, so the driver can confirm his ramps capabilities.
- Load Levelers - For long commodities or full deck utilization, a load leveler is available to extend the length of the upper deck. Multiple load levelers can provide the necessary support for the commodity and allow a step deck to function more like a flatbed. Load levelers can also be built by using material like 4x4 lumber.
- Stretch Trailer - A stretch step deck allows for the bottom deck to extend in length for hauling longer commodities that are generally oversize permitted for overlength.
- Coil Racks - These racks are made specifically for providing securement of steel coils preventing them from rolling or moving.
- Pipe Stakes - Found more commonly on flatbed trailers, they act as a fence for providing more securement in hauling certain materials. The stakes raise vertically at the sides of the trailer.
- TWIC Card - The "Transportation Worker Identification Credential" is a government provided card that allows a driver access to a secure areas of the nation's maritime facilities and vessels often called the ports.
- California Legal - California is a state that has specific axle spacing restrictions. These restrictions can often affect step deck trailers with a spread axle configuration. Some step decks don't meet these requirements and are, therefore, not allowed into California.
- Canada - Not all carriers, equipment, and drivers are allowed travel into Canada.
