Construction of chain stay is probably one of the most difficult tasks. Chain stay tubes are attached to the rear dropouts on one end and to the BB shell on the opposite end. Everything must be put together in perfect alignment as any imperfection will have impact on the alignment of the rear wheel and riding experience.

Core of the chain stay was prepared from styrofoam. I used three parts of styrofoam for one chain stay tube. Central core was rectangular on the section but shaped on the footprint. Two outer parts were cut as simple sloping blocks. Outer part was then glued onto central part. I cut overhanging styrofoam and glued second outer part to this construct, and again, cut excessive styrofoam.

I got the final shape of the chain stay by sanding. To protect styrofoam from bending, I prepared some kind of the frame from the plywood. I used pieces of sandpaper and moved them zig-zag on styrofoam part to get nice clean shape.

I cut the end that will be connected to dropout to make notch.

Created jag I foiled with couple of carbon cloth layers to make it stronger. At last, I finished the shape of this notch with sandpaper to get shape that will fit dropout.

I applied couple of carbon layers on the dropouts to align level of dropouts with adjacent styrofoam.

Finally, I wrapped the construct with 7 layers of carbon cloth.