<p>The device (1) has a wheel spoiler (2) arranged in an undercarriage area (5) before a front wheel (7) in a plane transverse to driving direction of a vehicle i.e. motor vehicle. The spoiler stays downward from the area in direction of a roadway. Guide fins (3) are limited on the spoiler and run in a vertical plane running parallel to the driving direction, where the guide fins partially extend within the area before the spoiler. A section (3a) of the guide fins provided in the area of the spoiler is longer than a section (3b) of the guide fins provided in an area below the spoiler.</p>
