This is the real thing! Save the world by not using fuel, use the power of your own body for fast transport,
and be able to repair and calculate the stuff with simple means.

Repair your crank / change your cogwheel and chain:

Build your own wheel, inclusive spoke lenght calculation (and the derivation of it):

Gearing of several standard hubs, and how to optimize.
Use the sheet "gearing_tables" to optimize chainrings and sprockets:

How to repair or even change a tube:


Tyre Sizes:


tire tables


to be continued