Ultrasonic transducers can be used to control friction. In case of a haptic texture actuated and explored simultaneously with the bare finger, this technology allows to reduce perceived roughness. In this article, we investigate its use to understand determinants of friction at contact. In the literature, a researcher recently suggested that microtexture perception was mainly determined by an interaction determinant: the commensurability of its asperities with epidermal ridges. In this paper, we levitate the skin with an air gap and thus cancel shear forces at contact. Results show that more important amplitude of vibration of the actuator is necessary to suppress friction at contact area when a directed movement is done along the epidermal ridges than across. This suggests that tactile perception of texture really depends on the bearing forces exerted by the surface on the skin.