Originally Posted by
cooperryder
. If you're going to spec two bottle cage boss locations why not the seat tube bosses rather than the under side of down tube?
I've wondered about this too. My winter project is an '84 Fuji TS III and has these bosses - top and underside of DT. Nothing on the ST. It may have been "a thing" in the early 80's. I've read that the underside cage was mostly used to hold stove fuel. As mentioned, that ST location may have been preferred for a frame pump.
My '87 Voyageur has all three ( maybe "normal" by late 80s) and I used the underside cage for fuel this past summer on the GAP. Fuel was only accessed once a day so under the DT is good enough. My pump is a very effective mini so I have no frame pump to store. Three cages worked well for me. I may use a clamp-on on the Fuji. Or nothing.