What Axle Configurations are Available for Drop Frame Chassis?

The axle configuration for your drop-frame chassis is an essential consideration for efficient transportation of your cargo.  Each type of axle configuration has different load limits and fuel efficiencies, and thus may be better suited to certain types of products. Key factors to consider when selecting the axle configuration for your drop-frame chassis include: the material to be transported, the container, load weight, road conditions, and the potential for encountering inclement weather conditions.

A dropframe chassis, also known as a tank container chassis, is the equipment preferred for intermodal transportation of bulk liquid tank containers. As the name implies, this equipment includes the chassis models in which the deck of the chassis is lowered (or “dropped”) to provide stability for constantly shifting liquid cargoes transported in tank containers and ISO tanks. The ISO tank container leverages the benefits of intermodal transportation for bulk liquids and the tank chassis was developed soon after to move these containers. Together these two inventions dramatically improved the efficiency of liquid bulk transportation.  

Tank chassis design has evolved in numerous ways as stronger, yet lighter materials are incorporated to improve fuel efficiency, stability and cargo weight. Here we will focus on one of the most important design features, the evolution of axle configurations.

Drop-Frame Chassis Axle Configurations

Closed Tandem

Closed Tandem Chassis

The closed tandem axle chassis was the original industry standard and for a long time it was the most common axle configuration available. This configuration has two sets of axles, one right behind the other, or “in tandem” (configuration not shown).  The dual axles provided the longer chassis frame with strength and stability for moving liquid cargo. 

The closed-tandem chassis typically has a ground clearance of 18 inches and a deck height of 42 inches. With such a low profile, the closed tandem chassis is often used for shorter hauls.

Triaxle Drop Frame Chassis

The quest to haul heavier loads led to the development of the tri-axle chassis.  As you might guess, this configuration adds a 3rd axle and four (4) more tires. Thus, accommodating the additional weight of heavier loads by distributing the weight over the load-bearing frame and tires. However, the additional axle adds to the overall tare weight of the chassis. This additional weight and tire surface area is beneficial when transporting heavy payloads in potentially adverse weather, but it must also be considered during route planning in order to maintain compliance with bridge laws. 

triaxle drop frame chassis with an extendable slider
This is a picture of a triaxle drop frame chassis with an extendable slider. There are two (2) different kinds of triaxle drop frames in our fleet.

Triaxle Drop Frame Chassis with Extendable Slider

Recently, an extendable slider was incorporated into the triaxle drop frame chassis model to improve operator safety. The triaxle dropframe chassis with extendable slider provides the following benefits:

  • A triaxle configuration suitable for hauling heavy payloads.
  • A 102” wide frame and lower center of gravity for improved stability.
  • An extendable slider that enables operators to hook up hoses from the ground. No climbing required.

Tandem Wide Spreadaxle Chassis

Tandem Wide-Spread Axle

The tandem wide-spread axle chassis was developed to provide additional hauling capacity over the original closed tandem configuration without the added weight of a third axle. These benefits were obtained by separating or “spreading” the axles. A wide-spread chassis evenly spreads the load weight of the cargo improving flexibility and stability during transport, even for heavier liquids. 

How to Choose the Right Drop-Frame Chassis Axle Configuration?

Select the chassis configuration which offers the optimum balance of load-bearing capacity, stability, equipment durability and fuel efficiency for your product!   

At Penn Intermodal Leasing, LLC, our existing chassis fleet includes models with a selection of axle configurations available for lease. Let us know about your product, transportation route and time frame and will work hard to match you with an efficient and durable chassis.    

If you are looking for additional features, we also offer enhanced safety features like full-frame walkways and a built-in rear step for ease of loading / unloading and maintenance. With Penn Intermodal Leasing, LLC, you can be sure you are getting a state-of-the-art chassis built for bulk liquid transportation.

Contact Us Today to Start your Drop-Frame Chassis Lease 

April Uhlenburg
April U

April has been working with Penn Intermodal’s Sales and Operations teams to educate clients on the benefits of leasing chassis for bulk liquid storage and transport since 2012.