The continuous pursuit of operational excellence in the tire manufacturing industry necessitates structured approaches to minimize production defects, improve resource utilization, and enhance product reliability. This study presents a comprehensive case study focused on the implementation of Lean Manufacturing tools within a high-volume production facility specialized in truck and bus radial (TBR) tires. The production line under investigation exhibited recurring defects on the sidewall region of the cured tires, referred to as defect F1, stemming primarily from condensation phenomena and steam management inefficiencies during the curing process. A detailed root cause analysis was conducted through structured brainstorming sessions, Ishikawa diagrams, and the 5 Whys method, revealing multiple converging causes including excessive internal pressure, improper drainage angles, degraded sealing interfaces, and inadequate vapor shielding. In response, a corrective action plan was deployed, integrating the installation of pneumatic OR-valves, realignment of machinery to induce gravitational drainage, application of protective skirts, and the adoption of preventive maintenance protocols. The interventions yielded a defect reduction from an average of 3.0% to 1.4%, representing a 39% improvement, well above the initial target of 20%. Additionally, a 30-second cycle time reduction was achieved, enabling an incremental output of 1,358 tires over a 23-day observation window and translating into more than 390 hours of direct labor saved. These results underscore the effectiveness of integrating Lean principles such as Kaizen, Single Minute Exchange of Die (SMED), and 5S within the framework of industrial tire manufacturing. The study not only validates the technical efficacy of the proposed interventions but also highlights the strategic value of Lean-based quality engineering for driving competitiveness in automotive component production.