improved cable guide for bicycle frames which has been found useful for improving the fatigue life of light weight bicycle frames and other stressed tubular structures . one or more welding or brazing - free dimple / bulkhead forming deformations produce strategically reduced stiffness zones so as to reduce peak stresses . the cable guide system also offers an improved method for routing control cables through the frame structure . a plastic cable nozzle insert is disclosed along with pyramid - shaped external dimples and contiguous bulkheads .