AERODYNAMIC OPTIMIZATION OF DISC BRAKES ON AERO BICYCLES
CONTEXT The importance of aerodynamics is getting bigger and bigger in road cycling. Bicycle manufacturers are able to optimize their bikes by using computer simulations and wind tunnel tests. For a number of years, disc brakes are becoming more popular on road bicycles. Their high braking performance in comparison to rim brakes makes them already the indisputable braking system in the mountainbike world. This masterthesis aims to combine both in a new aerodynamicaly optimized design. The focus was on the front brake as this brake has the biggest impact on the aerodynamics and also influences steering performance.
Iterations
Iterations
RESEARCH A measurement method was needed to compare the aerodynamics of the different concepts. The output had to be quantifiable in order to make quick numerical comparisons. Both CFD and wind tunnel tests can be used. During the prototyping phase, CFD is time consumming and requires specificic knowledge. Clay modeling facilitates iterative design using physical prototypes. These prototypes were then placed into a small scale wind tunnel. These results were compared to eachother and to the reference (conventionale caliper and fork), in this way the the number of concepts could be diverged. After the prototyping phase, the physical prototype was digitized in a CAD-model. CFD was used to visualize the airfoil around CAD-models, multiple iterations were made to optimize the concept. Further attention was paid to the assembly and maintenance of the new design.
RESULT The results of this thesis is an innovative brake system of which the disc brake caliper is structurally and aesthetically integrated in order to optimize aerodynamic performance. Integration of the components, seamless transition between the fork and the caliper and an aerodynamic caliper, causes a significant decrease in drag. During the final wind tunnel test. Under yaw angles form -10° tot 10°, the fork and brake are 16% procent more effective than the conventional design. Under these angles, 4.3 Watt can be saved. Not only the aerodynamics are taken into account but also the assembly and maintenance. The assembly process is derived from the conventional disc calipers which means there is little adaptation for the bike mechanics and users.
BERT HEIRWEG - BERT.HEIRWEG@HOTMAIL.COM