Locations
The most common location for a frame-mounted bottle cage is on the top side of the downtube. The most common location for a second frame-mounted bottle cage is on the front side of the seat tube. Small bikes and mountain bikes with rear suspension often do not have enough room for two bottle cages inside the main frame triangle.
Some touring bicycles have a third frame mounting location: under the downtube.
Bottle cages may be mounted behind the seat with a bracket that attaches to the seatpost.
Tandem bicycles may have as many as six bottle cages.
Recumbent bicycles may have bottle cages mounted to the steering mechanism or behind the seat back.
Read more about this topic: Bottle Cage