Abstract: Lightweight collapsible bicycle fenders are selectively attached to and detached from a bicycle frame by ties. The fenders are preferably formed from a sheet of durable flexible material, and the sheet of material is given sufficient rigidity and form to define the bicycle fender by lateral support elements. Flexible ties extend from the support elements. Once the fender is placed in the appropriate position, the ties are extended around opposite sides of a bicycle frame member and twisted together or otherwise fastened, thereby attaching the fender to an appropriate part of the bicycle frame and retaining the support elements and the flexible sheet of material in functional form as a fender.