Originally Posted by
baobao
For a road bike, why would anyone even consider 46/30? What do the professionals in Tour de France use in mountain stages?
Because that gearing works for them? You can still go over 30mph+ at a normal cadence with a 46 ring, so it's not like you're losing much at the top end and it might allow you to stay on the big ring for most of your riding. Meanwhile, the 30 ring will allow you to climb steep grades without having to grind it out at uncomfortable cadences.
As for your other question, 39/53 most of the time.