Draw a circle for the front wheel
Draw a circle for the rear wheel
Add a smaller circle inside each wheel for the hubs
Sketch the bike frame with straight lines connecting the wheels
Draw the main triangle of the frame
Add the seat tube, top tube, and down tube
Draw the handlebars above the front wheel
Add the fork connecting the front wheel to the frame
Draw the seat on top of the seat tube
Add pedals near the center of the frame
Draw the chain area around the pedals
Add the chain connecting the front and rear gears
Sketch the brakes, gears, and other small parts
Refine the wheel rims and spokes
Erase extra guide lines
Outline the final bike shape clearly
Add shading or color if desired