I just don't understand the need for a big ring on a touring bike! Honestly who pushes along at over 20mph and downhill I coast along. That's why my largest ring is 42t and my largest gear is 42x11 (103"). In fact gears on touring bikes are over rated.......I toured in England on a single speed bike (40x17) and had a great time, but for most tourists a gear range form 100" to 20" is more than enough and you can get that with a 42/26 crank and an 11/34 cassette. Also I don't see the need for half step if you are using a 9 speed cassette.