Contacts between particles in dense, sheared suspensions are believed to underpin much of their rheology. Roughness and adhesion are known to constrain the relative motion of particles, and thus globally affect the shear response, but an experimental description of how they microscopically influence the transmission of forces and relative displacements within contacts is lacking. Here, we show that an innovative colloidal-probe atomic force microscopy technique allows the simultaneous measurement of normal and tangential forces exchanged between tailored surfaces and microparticles while tracking their relative sliding and rolling, unlocking the direct measurement of coefficients of rolling friction, as well as of sliding friction. We demonstrate that, in the presence of sufficient traction, particles spontaneously roll, reducing dissipation and promoting longer-lasting contacts. Conversely, when rolling is prevented, friction is greatly enhanced for rough and adhesive surfaces, while smooth particles coated by polymer brushes maintain well-lubricated contacts. We find that surface roughness induces rolling due to load-dependent asperity interlocking, leading to large off-axis particle rotations. In contrast, smooth, adhesive surfaces promote rolling along the principal axis of motion. Our results offer direct values of friction coefficients for numerical studies and an interpretation of the onset of discontinuous shear thickening based on them, opening up ways to tailor rheology via contact engineering. Flows of dense microscopic particle suspensions can be found in many natural and industrial settings ( 1– 3), and have attracted much interest, as they can exhibit striking nonlinear rheological responses when subjected to shear stress, σ . Most commonly, they exhibit shear thickening (ST), whereby σ increases superlinearly with shear rate, γ ˙ . In this case, the viscosity of the suspensions increases with γ ˙ —either gradually (continuous shear thickening), or diverging at a critical shear rate (discontinuous shear thickening, DST). In shear jamming, the most severe form of DST, suspensions completely solidify under shear ( 3– 6). ST can be advantageous, for example in impact absorption ( 7), but it also causes widespread issues, in particular as it limits the processing speed of dense slurries such as concrete ( 8).