Project Overview
Item | Details |
|---|---|
Industry | Sports Equipment / Track Cycling |
Client | Yaya Ize, Japanese professional track cyclist |
Product | Custom bicycle handlebar extension bars |
Manufacturing Process | Metal 3D Printing |
Technology | Selective Laser Melting (SLM) |
Material | Aluminum (AlSi10Mg) |
Result | Race-ready one-piece extension used by Yaya Ize to set a new Japanese national record in the men's elite 4 km individual pursuit |
Background
Yaya Ize is a Japanese professional track cyclist competing at the elite national level. In track cycling, small gains in rider position, component weight, and aerodynamics can affect performance across every lap of a 250 m velodrome.
For the Japanese National All Track Cycling Championships, Yaya was preparing for the men's elite 4 km individual pursuit, a time trial event where riders must maintain a low, powerful, and aerodynamic position throughout the race.
The component at the center of this project was the handlebar extension, the forward-mounted arm that brings the rider's hands into the low, tucked position needed for pursuit racing. During the race, this part is constantly loaded by sprint force, rider weight during acceleration, and high-frequency vibration from the wooden track surface.
For this reason, the project goal was not simply to manufacture a handlebar extension, but to rethink its geometry, weight, and manufacturing approach to support Yaya's performance in a national championship event.
Challenges
Yaya needed a custom handlebar extension that could improve rider fit, reduce weight, and withstand the demands of elite-level pursuit racing—all within a tight competition preparation schedule.
Key challenges included:
Rider-specific fit: The extension had to match Yaya's reach, wrist angle, and low pursuit riding position instead of forcing the rider to adapt to a standard component.
Lightweight without compromising strength: The extension needed to be lighter than the welded reference while maintaining sufficient stiffness and strength to withstand sprint loads, rider weight during acceleration, and continuous vibration on the velodrome.
Complex aerodynamic geometry: The final design combined smooth aerodynamic surfaces with internal weight-saving features that were difficult to manufacture using CNC machining or welded fabrication.
Rapid development before competition: Multiple rounds of rider testing, design refinement, and prototype production had to be completed within Yaya's race preparation schedule, making conventional tooling and long manufacturing lead times impractical.
Solution
Unionfab selected Selective Laser Melting (SLM) with AlSi10Mg aluminum to overcome the limitations of conventional manufacturing while enabling rider-specific design, lightweight optimization, and rapid product development.
Iterative rider-specific design: After the initial STL concept was confirmed, Unionfab produced multiple prototype extensions in different geometries for on-bike evaluation. Feedback on reach, hand angle, cockpit balance, and overall comfort was translated into CAD refinements until the geometry matched Yaya's preferred riding position.
Lightweight structural optimization: Engineers optimized wall thickness and internal weight-relief features, removing material where it was unnecessary while preserving the primary load paths. AlSi10Mg was selected for its excellent strength-to-weight ratio, stable SLM printability, and suitability for thin-wall lightweight structures.
One-piece aerodynamic construction: Instead of designing around weld seams and bolt joints, the engineering team optimized the extension around the rider's hand position, front-end airflow, and load path into the handlebar and stem. SLM enabled the complex aerodynamic geometry to be manufactured as a single integrated aluminum component, eliminating welded joints while preserving structural continuity.
Rapid CAD-to-print iteration: Without the need for tooling or molds, each design revision could move directly from CAD to production. Multiple prototype cycles were completed within Yaya's competition timeline, allowing engineering improvements to keep pace with rider feedback and race preparation.
Production-ready finishing and verification: After printing, Unionfab removed supports, finished rider-contact surfaces, lightly refined the aerodynamic exterior, inspected critical mating features, and completed on-bike fit and load verification before the extension was approved for race use.
Results
The project delivered more than a custom handlebar extension. Using the AlSi10Mg handlebar extension manufactured by Unionfab, Yaya Ize set a new record in the men's elite 4 km individual pursuit at the Japanese National All Track Cycling Championships.
Beyond the race result, the project showed how metal additive manufacturing can deliver rider-specific, race-ready components within a competitive development timeline while meeting the structural demands of elite track cycling.
Key outcomes included:
Reduced front-end weight: The one-piece SLM aluminum extension weighed less than the original welded reference, reducing mass at the front of the bike without compromising structural performance.
Race-ready structural performance: The final component successfully completed on-bike fit and sprint-load verification, confirming the stiffness and strength required for elite pursuit racing.
Custom rider ergonomics: The final geometry matched Yaya's preferred reach, hand position, and riding posture, creating a component tailored specifically to the athlete.
Rapid development cycle: Multiple design iterations, rider evaluations, and production builds were completed within Yaya's championship preparation schedule without tooling or mold investment.
The result was a race-proven metal 3D printed handlebar extension that demonstrated how additive manufacturing can move beyond prototyping to produce lightweight, rider-specific, and competition-ready bicycle components.
Customer Testimonial
Future Outlook
The success of this project highlights the potential of metal 3D printing for low-volume, high-performance cycling components where customization, weight optimization, and rapid iteration are critical.
Beyond handlebar extensions, the same design and manufacturing approach can be applied to cockpit brackets, stems, clamps, lightweight structural inserts, and other custom-fit sports components.
Unionfab looks forward to continuing its collaboration with Yaya and supporting more athletes, teams, and sports equipment brands in developing performance-driven metal parts.
Acknowledgement
Unionfab thanks Yaya Ize for sharing his story and trusting the team with this performance-driven component. Special thanks also go to our engineering team for supporting the design review, prototype iterations, manufacturing, post-processing, and final validation throughout this project.
