The guy who is putting up the challenge said something about flip-flop being okay, but it would be more simple to have it be a single gear. Less to think about and worry about on the ride - apart from whatever hell your gear choice will cause you lol. I Everested on 42/23 (48") on a 7% hill, and even that felt big after 20 hours. Obviously, I think it would have to be a larger gear for overall speed on flats and just suck it up on the climbs. 71" would probably be a good in-between and is what the challenger recommends.
I'd probably undergear compared to what I thought I needed. I don't mind higher cadences so would probably go for something more like 65-69. There'd be nothing worse than pushing through treacle-like headwinds for days while overgeared.
The guy who is putting up the challenge said something about flip-flop being okay, but it would be more simple to have it be a single gear. Less to think about and worry about on the ride - apart from whatever hell your gear choice will cause you lol. I Everested on 42/23 (48") on a 7% hill, and even that felt big after 20 hours. Obviously, I think it would have to be a larger gear for overall speed on flats and just suck it up on the climbs. 71" would probably be a good in-between and is what the challenger recommends.