It is not certain that Dumoulin will win, but whatever happens in the remaining mountainous stages is only ultimately only going to define the time gaps going into the final stage time trial.
Let's imagine it in reverse, as though the time trial were before these last two mountainous stages, and let's imagine that (although the course is different and the condition of the riders is different) time gaps are in proportion to those on stage 10. The Milan stage is to all intents and purposes 3/4 of the length of the Montefalco stage, so let's start the calculations of possibilities from that proportion (1/4 seconds rounded down, 1/2 and 3/4 rounded up).
Name current gap + 3/4 of stage 10 = deficit
Quintana: 0:31 + 2:09 = 2:40
Nibali: 1:12+ 1:32 = 2:43
Pinot: 1:36 + 2:01 = 3:37
Zakarin: 1:58 + 1:45 = 3:43
Pozzovivo: 2:07 + 2:17 = 4:14
Mollema: 3:17 + 1:42 = 4:59
Kruijswijk: 5:48 + 2:01 = 7:49
Yates: 7:06 + 2:00 = 9:06
Jungels: 7:34 + 0:42 = 8:16
Formolo: 7:59 + 3:03 = 11:02
I can't imagine (barring disaster) anyone other than the first 4 on this list taking places 2 to 5 at the end of the race, but are these about right for the stage 21 gaps? What think you?
Let's imagine it in reverse, as though the time trial were before these last two mountainous stages, and let's imagine that (although the course is different and the condition of the riders is different) time gaps are in proportion to those on stage 10. The Milan stage is to all intents and purposes 3/4 of the length of the Montefalco stage, so let's start the calculations of possibilities from that proportion (1/4 seconds rounded down, 1/2 and 3/4 rounded up).
Name current gap + 3/4 of stage 10 = deficit
Quintana: 0:31 + 2:09 = 2:40
Nibali: 1:12+ 1:32 = 2:43
Pinot: 1:36 + 2:01 = 3:37
Zakarin: 1:58 + 1:45 = 3:43
Pozzovivo: 2:07 + 2:17 = 4:14
Mollema: 3:17 + 1:42 = 4:59
Kruijswijk: 5:48 + 2:01 = 7:49
Yates: 7:06 + 2:00 = 9:06
Jungels: 7:34 + 0:42 = 8:16
Formolo: 7:59 + 3:03 = 11:02
I can't imagine (barring disaster) anyone other than the first 4 on this list taking places 2 to 5 at the end of the race, but are these about right for the stage 21 gaps? What think you?