The leaf spring suspension is extensively used in the heavy vehicle sector because of their affordability and strong load-carrying ability. Conventional spring steel leaf springs, though, account for a substantial portion of unsprung mass (15-20%), degrading fuel economy and promoting exhaust emissions. The four composite materials – Basalt Fiber Reinforced Polymer (BFRP), Hybrid-Basalt-Natural Composite, Recycled Carbon Fiber Composite (RCFC), and Nano-Reinforced Polymer – are evaluated here as reduced mass, corrosion-resistant substitutes for spring steel. Through Finite Element Analysis (FEA) in ANSYS, we tested these materials under static loads of 100-300 kN for deformation, equivalent stress, strain, fatigue life, safety factor, and damage accumulation. Findings reveal Nano-Reinforced Polymer excels others with low deformation (0.89 mm at 300 kN), high fatigue life (3.11×10^6 cycles), and little damage (0.01), resulting in up to 70% weight savings over steel (7850 kg/m³ vs. 1300 kg/m³). RCFC provides uniform performance (0.85 mm deformation, 1.00×10^8 cycles at 200 kN), whereas BFRP and Hybrid-Basalt lack performance at heavy loads. Numerical calculations supported FEA outcomes with errors less than 12% for deformation and stress. This study meets the need for light weight, long-life suspensions to improve vehicle dynamics, diminish emissions, and facilitate green transport, presenting a comparative basis for material choice in heavy vehicle usage.