Resin Transfer Mold (RTM)

Engineering Integrity from Within

Resin Transfer Molding (RTM) is a benchmark technology in aerospace and high-performance automotive engineering, yet remains exceptionally rare in the cycling industry. At Sunremo, we have pioneered its application to transform our precisely braided carbon sleeves into solid, exceptionally strong, and resilient frames. Our implementation of RTM drastically minimizes structural imperfections and enables the creation of bicycles with unparalleled integrity.

Eliminating Defects, Maximizing Strength

RTM represents the most effective method to minimize defects within a composite structure. By injecting high-performance resin under controlled pressure between precisely matched, rigid external and internal molds, air pockets are completely evacuated and interlaminar voids are eliminated. The resin flows only within the predetermined channels defined by the molds, ensuring that every frame assumes its exact intended shape and wall thickness. This results in exceptionally high-tolerance, uniform, and consistent quality, yielding a near-net-shape product of remarkable integrity.

Precision Quality Through Pressure & Control

The combination of high-pressure resin injection and controlled temperature ensures thorough, uniform fiber wetting and optimal consolidation. This process virtually eradicates the microscopic voids and dry spots that can compromise strength and long-term durability. The result is not only exceptional structural performance but also remarkable consistency—frame-to-frame variance is minimized, guaranteeing that every Sunremo bicycle delivers the exact same premium ride quality.

Flawless Inside and Out

The use of dual-sided, rigid molds allows for the creation of complex external geometries and sophisticated internal reinforcement structures. Unlike single-sided molding methods, RTM ensures that internal surfaces are as perfectly formed, smooth, and structurally sound as the exterior. This contrasts sharply with prepreg processes that rely on vacuum bags, which can lead to uneven resin distribution, fiber wrinkling, and imperfect internal surfaces that are hidden from view but critical to performance.

Reducing Our Environmental Impact

Sunremo’s RTM process incorporates a sustainable approach to tooling. After curing, the internal wax mandrels are melted out and fully recycled for reuse, leaving no residual material inside the frame. This stands in contrast to standard prepreg molding, which often leaves non-structural plastic bagging materials or expanded polystyrene (EPS) foam cores permanently trapped within the finished structure. Our method reflects a commitment to performance that is matched by a responsibility to thoughtful manufacturing.