Stability analyses in slopes require mechanical soil properties. Many laboratory procedures had been developed to obtain mechanical parameters: triaxial undrained tests, direct shear tests, and oedometer tests to mention a few. This paper evaluates the feasibility of rheometer tests results to develop a stability model of clay and silt slopes. SEEP/W and SLOPE/W analyses were developed in GeoStudio, modeling drought and rain periods to evaluate the effect of matric suction in shear strength. Results are compared with similar analysis found in the literature, where traditional tests had been applied. The safety factor evolution has been computed during different weather conditions, where the soil strength evolution has been considered. This research revealed that the rheometer tests are feasible to understand the evolution of slopes’ stability.