The ornamental design for an airtube for pneumaticbicycle tires, as shown and described.
FIG. 1 is a perspective view of a first embodiment of an air tube for pneumatic bicycle tires incorporating our new design, it being understood that the exterior pattern repeats circumferentially throughout the outer circumference;
FIG. 2 is an elevational view of one end of the air tube shown in FIG. 1;
FIG. 3 is an elevational view of an opposite end of the design as shown in FIG. 1; and,
FIG. 4 is an elevational view of one side of the design as shown in FIG. 1.
The broken lines in the drawings depict environmental subject matter only and form no part of the claimed design.