Abstract: A lightweight bicycle frame having improved rear fork rigidity constructed by attaching the front section of a left and a right subassembly each having a "C" shaped cross-section and each being the mirror image of each other to which is attached to the rear section of the connected subassemblies to form the rear fork of the frame a third subassembly substantially in the form of an oval folded about its minor axis approximately 160 to 166 degrees which provides improved rigidity to said rear fork and a front fork similarly constructed from two "C" shaped subassemblies which are connected to each other at a tap section thereof to which is attached at a lower section thereof a third "U" shaped subassembly which provides further lightweightness to the bicycle assembled from said front fork.