1.Which do most TDF riders use - tubulars or clinchers? (I really don't
know)
Go to cyclingnews, and look through their tech articles about bikes of
the pro peloton. If you research a few hours you can probably give us a
definitive answer. Heres an url to get you going: http://www.cyclingnews.com/tech/#tour
I'll guess it's clinchers 60%, sew-ups 30%, other 10% :). Someone that
reads this group and saw the tour this year might give us an answer.