The ornamental design for a bumper for vehicles, as shown and described.
1. Bumper for vehicles
1.1 : Perspective
1.2 : Front
1.3 : Back
1.4 : Left
1.5 : Right
1.6 : Top
1.7 : Bottom
1.1 is a perspective view of a bumper for vehicles showing our new design; 1.2 is a front elevation view thereof; 1.3 is a back elevation view thereof; 1.4 is a left side elevation view thereof; 1.5 is a right side elevation view thereof; 1.6 is a top plan view thereof; and 1.7 is a bottom plan view thereof.