This research aims to design a formula for natural rubber composites using different types and doses of secondary accelerators (N-Cyclohexyl-2-benzothiazole sulfenamide (CBS) and Diphenyl Guanidine (DPG)). The bridge bearing pads are made from natural or synthetic rubber, such as chloroprene. Although natural rubber is abundant, high-quality natural rubber bridge bearing pads often fail compression set and accelerated aging requirements. Mechanical properties and swelling characteristics of NR composites were evaluated. Rheometer tests showed that using MBT and CBS as accelerators improved curing behavior and mechanical properties. Increased secondary accelerators raised maximum torque and decreased minimum torque. The results show that using the highest percentages of both accelerators, CBS and DPG, yields significant improvementsin rheological and mechanical properties. The tensile strength improved from 18.3 MPa with zero CBS content to 31.53 MPa with the highest CBS content. Using DPG as a second accelerator improves tensile strength from 18.3 MPa to 27.37 MPa. Also, elongation at break for NR accelerated with CBS and DPG was improved. Rheometer characteristics showed that increased crosslinking with second accelerator absorption is directly proportional, as presented by scorch time measurements. Both accelerators achieved similar hardness values of 70 Shore A blending these accelerators significantly affects rubber properties.