Release Date
November 29th, 2023
Open Date
January 3rd, 2024
Due Date(s)
February 21st, 2024
Close Date
February 21st, 2024
Topic No.


Durable Wheel End Drive for Amphibious Vehicles


Department of DefenseN/A


Type: SBIRPhase: BOTHYear: 2024


The Department of Defense (DOD) is seeking proposals for the topic of "Durable Wheel End Drive for Amphibious Vehicles" as part of their SBIR 24.1 BAA solicitation. The objective is to design and develop a new or improved drive axle for the Amphibious Combat Vehicle (ACV) with greater durability in an amphibious environment. The current wheel end drives on the ACV use traditional Constant Velocity (CV) Joints that require excessive maintenance. The DOD is interested in innovative approaches to develop a more durable wheel end drive, either by protecting the current CV Boots, replacing the Boot with a more durable material, or redesigning the joint. The proposed concepts should address extreme operating environments, including temperature ranges from -40°F to +120°F, hot desert blowing sand, salt water immersion, and operation in surf zones and mud. The wheel end drive should also be able to withstand various loads and forces, such as 3 g-force vertical load, 0.7 G horizontal load, NATO tree impact, and fatigue loads for a 30-year vehicle life. It should support steering on slopes and have specific torque, angle, and rotation speed capabilities. The project will be conducted in multiple phases. Phase I involves designing a more durable wheel end drive and demonstrating its feasibility through modeling or testing. Phase II focuses on developing a scaled prototype for evaluation and refining it based on performance goals. Phase III involves transitioning the technology for Marine Corps use, integrating the prototype into a vehicle, and providing support during test and validation. The technology has potential applications in large military vehicles and amphibious rescue vehicles, with potential benefits including weight and complexity reduction in the suspension. The solicitation was released on November 29, 2023, and the application due date was February 21, 2024. For more information and to access the solicitation, visit the DOD SBIR 24.1 BAA page on ( or the DOD SBIR/STTR Opportunities page (




OBJECTIVE: Design and develop a new or improved drive axle for the Amphibious Combat Vehicle with greater durability when subjected to operation in an amphibious environment.


DESCRIPTION: The United States Marine Corps is fielding the Amphibious Combat Vehicle (ACV) designed to operate over harsh off-road terrain and in oceans and rivers. The ACV currently uses traditional Constant Velocity (CV) Joints on the wheel end drives that require excessive maintenance because they develop holes and tears in the inside and outside CV Boots. The Marine Corps is interested in innovative approaches to develop a more durable wheel end drive. The design must protect the current CV Boots, replace the Boot with a more durable material, or redesign the wheel end drive joint so that it does not require a grease filled boot covered joint.


Proposed concepts should:

  • Address the ability to function in extreme operating environments which include but are not limited to -40 degrees Fahrenheit (°F) to +120°F, hot desert blowing sand, full salt water immersion, operation to and from the beach in surf zones up to 6 foot Significant Breaker Height (SBH) and mud (soft soil of 30 Rating Cone Index (RCI)) which includes suspended abrasive items such as rocks, gravel, sand, and coral.

  • Allow for terrain traverse with combined 3 g-force (G) vertical and 0.7 G horizontal load on suspension station, racking load at diagonal corners for 1 G vertical load, North Atlantic Treaty Organization (NATO) tree impact (5" tree at 32 kilometers per hour (kph)-8365 pound equivalent static load), and fatigue loads for 30 year vehicle life.

  • Allow for a maximum of 4,350 newton-meters (NM) of torque, a maximum angle of 40 degrees (short duration), and a maximum rotation speed of 2,682 RPM.

  • Support steering in the forward and reverse directions on 40% side slopes and ascending, descending, starting, and stopping on a dry hard surfaced longitudinal slope up to and including 60% grade in both forward and reverse direction.


PHASE I: Design a more durable wheel end drive in consideration of the operating environment in which the drive system will be exposed. Demonstrate, via modeling or testing, the feasibility of the concept(s) in meeting Marine Corps’ needs and establish that the concept can be developed into a useful product for the Marine Corps. Feasibility will be established by material testing and analytical modeling as appropriate. Provide a Phase II development plan with performance goals and key technical milestones that will address technical risk reduction.


PHASE II: Develop a scaled prototype for evaluation. The prototype will be evaluated to determine its capability in meeting the performance goals established for the Marine Corps’ amphibious vehicles. System performance will be demonstrated through prototype evaluation and modeling or analytical methods over the required range of parameters. Evaluation results will be used to refine the prototype into a design that will meet Marine Corps requirements. Working with the Marine Corps, prepare a Phase III development plan to detail the strategy for transitioning the technology for Marine Corps use.


PHASE III DUAL USE APPLICATIONS: Support the Marine Corps in transitioning the durable wheel end drive system for Marine Corps use. Working with the Marine Corps, integrate the prototype wheel end drive system into a vehicle for evaluation to determine its effectiveness in an operationally relevant environment. Provide support to the Marine Corps during test and validation to certify and qualify the system for Marine Corps use. Develop manufacturing plans and capabilities to produce the system for both military and commercial markets.


This technology is directly applicable to large military vehicles such as the Marine Corps ACV.

Successful development and characterization of a durable wheel end drive system has direct application to various military and commercial applications such as amphibious rescue vehicles. Reductions of weight and complexity in the suspension can be of substantial value.



MIL-STD-810G Environmental Test Methods and Engineering Guidelines.
MIL-STD-889B Dissimilar Metals.
Description of a flex joint/Giubo.


KEYWORDS: Provide a minimum of six key words separated by semicolons. Drive; axle; constant velocity joint (CV Joint); boot, Giubo; amphibious