Originally Posted by
etsisk
thanks for the info! My bottle cage is actually on my down tube, but I want to add another one on the seat post. Looking more closely at my bike, I've realized that I DO actually have a second set of braze-ons, on the downtube, but on the BOTTOM of the tube (in my naivety I didn't even think to look there). I could use that one as well, but it seems mighty exposed to road hazards, etc.
That's a typical place for touring water bottle cages. You don't necessarily drink from that bottle and you just transfer the contents to the other bottle or you rinse off the valve. The seattube, by the way, was usually kept clear so that you could mount a frame pump there. Today's minipumps (Topeak Road Morph is the best one) fit next to the water bottle cage or under the top tube.
I like the
Elite VIP water bottle clamp for an extra cage. Works well and looks a lot better than many of the alternatives.