FIG. 1 is a reduced perspective view of an illuminable light tube for bicycles showing my new design, with the broken line showing for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a rear elevational view thereof;

FIG. 6 is a left side elevational view thereof; and,

FIG. 7 is a bottom plan view thereof.