Originally Posted by
Commando303
I'm not sure whether you're being facetious, but,
1) Your chain's not relying on water for lubrication.
2) Your tires do best when they're in constant contact with the pavement; water gets in the way of that, it doesn't enhance it.
3) Moisture in the air will, if anything, increase its density, thereby increasing the resistance you face.
Anyway, personally, I don't feel rain makes me a faster biker; it does slow me down. I have reduced visibility (in both ways: it's harder for me to see stuff, and it's harder for others to see me) and increased stopping-time. It also can make my hands feel slippery on the grips, and can annoy me as I keep having to wipe water from my eyes.
+1 and don't forget you really have to be careful of manholes, railroad tracks, lane dots, fog lines, etc., which are all dangerously slippery in the rain. Then there are the puddles - maybe it is fun to splash through them but you never know when one is concealing a pothole (even if you ride the route regularly a pothole could have opened up since the last time, which heavy rain makes a distinct possibility). Also your chances of a flat go way up in the rain as well. Don't get me wrong ... I like to ride and riding in the rain doesn't bother me in the least and rain or not I'd rather be on my bicycle than in a car, but I really don't think it makes you faster, at least if you are riding with the caution such conditions demand.