Since the introduction of water cooling to offroad performance motorcycles in 1981 [1], the most integral part of engine thermal management has remained unchanged. The traditional design of radiators uses winding louvers to exchange heat with the surrounding air in repeated zigzagging patterns (shown in Figure 1). This design is far from optimized in 2023. The modern methods of maximizing heat exchanger efficiency by using optimization software, such as nTop, and additive manufacturing methods, such as Direct Metal Laser Sintering (DMLS), have not yet been utilized in motorcycles. These methods have been demonstrated thoroughly in heat sink manufacturing, shown in Figure 2.

As of 2021, the global off-road market was valued at USD 14.34 billion [3] with professional race teams spending millions of dollars every year to produce the best performing machine to represent their respective brands. One notable example is that every factory team for professional motocross spends tens of thousands of dollars on titanium bolts alone to remove a few grams of weight [4]. In the constant pursuit of improvement in racing, an integral part of motorcycle performance is not only overlooked, but underutilized. There are two main benefits of optimizing radiators: ergonomics and engine performance.

Radiators severely widen the width of a dirt bike, making it much less maneuverable. Shown in Figure 3, the radiators account for almost a 26 cm increase in width from the center of the motorcycle to the front. Increasing radiator efficiency through optimization would allow for a reduction in size of the component and increase the ergonomic maneuverability.

Radiators are also often the first point of failure in racing, especially in strenuous conditions. Mud and debris clog radiators in racing events and severely limit engine performance that frequently results in damage to the engine. An optimized radiator would be better equipped to fight a cooling deficit by providing increased heat dissipation per unit area. Another issue in motocross is wrecks. Radiators, because of their dramatic width, are often the first part of the motorcycle to contact the ground. Ironically, radiators are also one of the most sensitive pieces of the vehicle being made of thin aluminum. An optimized radiator would provide the performance needed to reduce the size of the radiator and make it much less prone to race failing breakages.

Overall, the demand is present in a substantial market, and the solution to it is achievable. Producing a maximized performance radiator would enhance the ergonomics, durability, and the engine performance of any motorcycle.

Sources:
[1] Cycle World. (1981, November 1). Yamaha YZ125H: Cycle World: November 1981. https://magazine.cycleworld.com/article/1981/11/1/yamaha-yz125h
[2] Recorded training: Heat sinks. nTop. (n.d.). https://learn.ntop.com/recorded-training-heat-sinks
[3] Off-road motorcycle market size & share report, 2021. Off-road Motorcycle Market Size & Share Report https://www.grandviewresearch.com/industry-analysis/off-road-motorcycle-market-report
[4] Weisel, J. (2022, June 25). The when, where, how & why of titanium bolts. Motocross Action Magazine. https://motocrossactionmag.com/ask-the-mxperts-the-when-where-how-why-of-titanium-bolts/