Freedom Concepts Inc. (FCI) is a pioneer of customized recreational mobility devices for people with disabilities. One customizable parameter is the crank arm length. Team 19 designed an adjustable crankset for sales staff to use during Demonstration Events to replace the current slow and tedious crank arm sizing process, providing draft engineering drawings, CAD models, and a costed Bill of Materials. The arms, whose length varies between 3” and 5” in 1/2” increments, are compatible with standard FCI tricycle components, and are safe, straightforward to use without prior training, and functional during test rides. The arms fit compactly within the design space, are durable in transportation and repeated use, and avoid interference with other tricycle components. The final design consists of a solid bar sliding within a hollow sleeve. The solid bar is held in place by two spring-loaded pins. Each crank arm contains through-holes shaped to accommodate the standard JIS square taper and 9/16”-18 threaded pedal connections. A built-in Spider Arm interface is used to connect the right-hand crank arm to commercially available 26T or custom-cut 32T chainrings via steel chainring bolts. The hollow sleeves must be casted from UNS A07130 aluminum alloy in Taiwan by the current FCI crank arm supplier, while the solid bars must be machined from Aluminum 6061-T6 by Manitoban metal shops. All finishing processes can be conducted locally. Each crankset is expected to cost approximately $255 in total to manufacture. The team performed hand calculations to prove design safety and durability in transportation and repeated use. For a maximum load of 350 lbf, the crank arms were successful in all failure modes. Finite Element Analysis showed no unexpected stresses unaccounted for by software limitations, and Failure Modes and Effects Analysis confirmed the final design is not exposed to severe risks. The House of Quality confirmed the arms meet all identified needs. For prototyping, the team recommends FCI purchase and modify existing crank arms. Prototyping may assist with the development of a secondary solid bar allowing adjustments to a 2.5” length. The team also recommends FCI conduct quality tests on the casted hollow sleeves prior to use. FCI may wish to investigate the use of threaded inserts to extend crank arm longevity, especially if the design is adapted for large-scale commercial production in the future. Commercialization would provide customers with an additional customization option, potentially increasing adaptive tricycle sales. Increasing production levels would also decrease the manufacturing costs per unit.