The large defecits of time made up in the Pererio & Armstrong Victories mentioned, came about from breakaways gaining big chunks of time, Pererio (sp?) benefiting from being part of one long breakaway, and Armstrong making up time on on early break that his team allowed to occur early in the race.
Another significant deficit made up in recent years (which did not come about through time gained in a long break ) was that of Marco Pantani in 1998.
He entered the Pyrenes (sp?) after the first long time trial 5.04 down on favourite Jan Ullrich and ended up winning Le Tour by 3.21 (he made up 8.25 secs in total) but 8.57 secs was his gain during that epic ride once the race hit the Alps on stage 15 attacking in the mist and rain on the Galibier on the way to the mountain top finish at Les Deux Alps.
So if I read it right so far the largest deficit made up by GC contender to other GC contender
(Pereiro and Armstrong, etc. making back big time in mountains on earlier non-GC contender leaders who gained in long breaks on flat stages not included) is:
Pantani over Ulrich in 1998: total time made up 8:25 (including winning margin)
Lemond over Hinaul in 1986: total time made up 7:30 (including winning margin)
So 7 - 8 minutes is the most in the modern era.
With Ventoux being positioned 3 weeks into a GT, how much time (considering tired nature of riders and having to ride "like there is no tomorrow" because there isn't) could this years TDF main GC contenders make up on Ventoux?
Answer the Ventoux question twice considering two assumptions.
GC Contender "A" has incredible day and rest do average. How much does Contender "A" gain over the field?
GC Contender "A" has incredible day, GC contender "B" has bad day (but not full on 'bonk'), rest of field does average. How much does Contender "A" (good day) make up over Contender "B" (bad day sans 'bonk')