Originally Posted by hubs
What style is the bike? I think her ride position will make a big difference. The more upright, the easier gear she'll need. Way up, heavy frame ... 38-19. Down toward a drop position a much harder gear is easy to push.
I'm just starting out and have bad knees so I'm going 44-20 (flatland here). I ride quite a bit and do like to spin. I still have the freewheel & cog and 44-22 is sweet, but I think I want just a bit more for moving along.
Good Luck and just make it clear to her that it is something you can change.
The riding position is forward, it's an old Raleigh Capri, she'll be on the hoods 99.99999% of the time. I also have the forward reach of the handlebars level to the ground and the levers back a bit so she's not so stretched out. I plan to put pics up this weekend.
Gosh it's about 50/50; stay at 17 or go up to 21....