Influence of Wheel Stiffness on Brake Drum Deformation in Commercial Vehicles

This study investigates the influence of wheel structural stiffness and wheel configuration (single- and dual-tire) on brake drum deformation in commercial vehicles equipped with pneumatically actuated drum brakes. A comprehensive multi-method approach was adopted, combining on-vehicle measurements, controlled bench testing using two- and three-dimensional optical metrology, and Finite Element Analysis (FEA) of the rear axle assembly. Three- wheel configurations were evaluated: a dual-tire arrangement (Configuration A) and two single-tire designs with distinct stiffness characteristics (Configurations B and C). Radial distortion was quantified using the displacement difference between the bottom and top regions of the brake drum (ΔZ). The results demonstrate that wheel stiffness and the offset between the wheel-disc attachment point and the ground reaction force are dominant factors governing brake drum deformation. The brake drum equipped with dual-tire configurations exhibited minimal ΔZ, whereas the brake drums equipped with single-tire configurations, particularly the least stiff Configuration C, showed pronounced outward radial displacement and increased deformation asymmetry. Design evaluations conducted under the worst-case configuration confirmed these findings, showing an effective reduction in brake drum deformation achieved by increasing the brake drum collar thickness (–36.1%; +6 kg) and by increasing the wheel rim thickness (–27.8%; +4.5 kg).