Originally Posted by
southpawboston
...frames can and do collect water, but mostly from being left in the rain and from being ridden without fenders. if you don't leave your bike out in the rain, and you have fenders, there's really little chance of water accumulating in your frame. many frames have drain/vent holes in the seat stays, fender stays, and fork blades, but what is often overlooked is the bottom bracket shell. if any water is to accumulate anywhere, that's usually the place. it's like a catch basin...
If you do ride without fenders, the biggest culprit is the seatpost, the ones with the open top. The spray from the rear tire hits the underside of the seat then drips down though the opening of the post. This is one time that you literally want to stick a cork in it, then seal the edges with caulking.
One other concern, though it may not be so big in California, is condensation. In more northernly climates, if you store your bicycle in a heated room, then take it outside into the cold, the warm, moist air inside the tubes, will condense. This is a major concern for winter commuters in northernly climates.
The alternative is to ride an aluminum or carbon fibre frame. However, as previously noted, winter road salt is extremaely harsh and pits aluminum. Not sure about carbon fibre. (Maybe we've finally found a valid use for the stuff.
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