Abstract: Arrangement for an optical speed indicator intended to form part of the system for the anti-lock braking of a vehicle wheel. The speed indicator has a rotationally symmetrical device (1) operatively connected with the wheel, said device being executed with equidistant openings (4) or the like, a light source (2) positioned on one side of said device (1) and so arranged as to illuminate said openings (4), and a detector (3) positioned on the other side of said device (1) and so arranged as to generate a signal pulse each time it is struck via an opening (4) by light from the light source (2). A characteristic feature of the invention is that the arrangement includes a nozzle (8) communicating with the brake cylinder (7) of the vehicle wheel in such a way that the quantity of air discharged from the cylinder (7) via the nozzle (8) during braking produces a jet of air so arranged as to prevent the speed indicator from becoming contaminated with dirt.