I would imagine that there are basically four things that are the major hurdles to winning the Giro, Tour and Vuelta in the same year:
1. Peaking at the proper time for each or at least having good form. If one's strategy were to win all three it would affect certain tactics and strategy in each individual GT and stage. The second guessing on exactly what to do when would be mind boggling.
2. The psychological torture involved in being that single minded, focused, and stressed from May through September. By the time you got to the Vuelta I imagine it would be pretty tough to get on the bike some mornings for 200k.
3. Staying healthy and avoiding accidents and injury. Not falling off, getting in a crash or getting sick over some 6000k of stage racing seems statistically unlikely to me.
4. Having a super human team of dedicated domestiques to help and protect--this team would have to be super consistent and on board with the plan.
Of these four I think that # 3 is the most likely derail the attempt.
1. Peaking at the proper time for each or at least having good form. If one's strategy were to win all three it would affect certain tactics and strategy in each individual GT and stage. The second guessing on exactly what to do when would be mind boggling.
2. The psychological torture involved in being that single minded, focused, and stressed from May through September. By the time you got to the Vuelta I imagine it would be pretty tough to get on the bike some mornings for 200k.
3. Staying healthy and avoiding accidents and injury. Not falling off, getting in a crash or getting sick over some 6000k of stage racing seems statistically unlikely to me.
4. Having a super human team of dedicated domestiques to help and protect--this team would have to be super consistent and on board with the plan.
Of these four I think that # 3 is the most likely derail the attempt.