As a 1st-time watcher of the Tour on TV (I don't have cable/satellite so I only see the weekly summaries for one hour once a week), I don't understand how the time trials work.
What is the purpose of the time trials? Why are they shorter than regular races? Why are riders staggered in start times? How is the starting order determined? How do their race times factor in to the overall race total?
How many of the 21 stages are time trials, and which stages are they?