This study aims to investigate the morphological, mechanical, and rheological properties of silica-filled styrene-butadiene rubber (SBR). We investigated four industrially common rubbers, i.e., SBR1502, SBR1712, SBR1763, and SBR72612, filled with 55 phr of silica. These rubbers differ in terms of molecular weight, molecular weight distribution, and synthesis methods. In the first part of this research, nanosilica (NS) powder was synthesized on an industrial scale from sodium silicate and used as a filler to fabricate compound specimens. A high-quality NS (>97.8% nanosilica) with a particle size in the range of 8.64–18.31 nm and a surface area of 320-360 m2/g was synthesized and measured by FESEM and BET analysis respectively, and were then mixed with the aforementioned rubber using internal mixer (Bunbury) at the temperature of 150℃ (first step), 90 ℃ (final step) and 380 rpm for 2 minutes in each step. The molecular weight distribution comparison revealed that the SBR72612 has the narrowest molecular weight distribution and the highest molecular weight. Furthermore, the mechanical properties analysis showed that the SBR1502/silica sample had the highest elongation and the lowest Young modulus by 720% and 1.55 MPa respectively. Increasing the molecular weight distribution and molecular weight increased the Young modulus and declined the elongation. In the SSBR/SiO2 sample, which has the narrowest molecular weight distribution and the highest molecular weight, the elongation decreased by approximately 55% and the Young modulus increases by 18%. The rheological investigation showed that the SBR72612/Silica sample had the lowest loss factor, meaning that the tire composed of this sample is expected to show the lowest rolling resistance. The strain sweep rheological examination of the samples in one percent of constant tension revealed that the higher storage modulus, the more significant the volume of force, which is consistent with the results of mechanical properties