A Structural-Comfort Integrated Approach to Optimized Geometries for In-Wheel Suspensions in Urban Micromobility Vehicles

The development of suspension systems for urban micro-mobility vehicles, such as bicycles and e-bikes, requires balancing effective road filtering with structural simplicity. Traditional solutions, such as telescopic forks and rear shock absorbers, face significant challenges related to weight, bulk, and mechanical complexity, which increase production and maintenance costs. The integration of in-wheel motors into wheel hubs further complicates the design by increasing unsprung mass and vertical vibrations, negatively affecting ride comfort. The In-Wheel Suspension (IWS) system offers an innovative solution by incorporating elastic and damping elements directly into the wheel rim, eliminating the need for frame modifications and reducing overall weight. This study proposes an integrated approach to optimising the internal geometries of IWS elastic elements, using structural analyses with LS-Dyna and dynamic simulations in the Simulink environment for comfort assessment. Results demonstrate that optimising the geometry of spokes and rims significantly reduces stiffness variations and self-induced vibrations, with enhancements in ride comfort and resistance to fatigue. The optimized IWS design minimises discomfort peaks at critical speeds and improves vibration attenuation. However, the high average stiffness limits filtering performance at speeds above 10 km/h. While IWS systems represent a promising alternative to traditional suspensions due to their advantages in weight reduction, compactness, and construction simplicity, further improvements—such as the use of composite materials and alternative geometries—are necessary to further increase comfort and to ensure structural resistance to variable loads.