SuperSid
Old School Hero
It just slides on, the small tolerance makes it a tight fit. I don"t use the pump, it's purely there for aerodynamic reasons. There is a little clip that fills in the gap once the pump is fitted to the frame. It's a Zéfal pump
The aero section I used is basically a Scott Foil tube section, I tested a few variants in front of a cylinder in Autodesk flow design - which is a very basic virtual wind tunnel. It's not the most accurate software but it's good enough for comparing simple shapes.
The round seat tube isn't the best shape for an airfoil tail so I added some turbulator tape all over the place to trip the airflow and reduce the wake, golf ball style. I learnt a lot about bike aerodynamics with this little project.
Here are the 3 parts I printed in PLA
