Shapes as a function of the Bond number Boα for different values of the relaxation ratio R. For each system, the drop becomes more asymetric and eventually unstable as Boα increases. R = 2.24: Boα = 0.095, 0.239, 0.409; R = 1.19 × 102 : Boα = 0.103, 0.480, 0.496; R = 1.07 × 104 : Boα = 0.107, 0.404, 0.442. The equivalent radius R0 of the droplets is of the order of the capillary length ℓc = (γ/(ρg))1/2 of the liquids in all cases. The pinch observed behind the front of the droplet at large R is a visual artefact: the equilibrium contact angle is greater than π/2 for these systems (see table 1) and the liquid/air interface hangs over the contact line during sliding. Orange arrow in the bottom left picture: direction of motion. Scale bar: 2 mm