Hey all -- I'm trying to figure out what to do with the gearing on my Cyclocross bike. I use it for offroad rides, and also commuting, and I intend to eventually use it for CX races when I feel a little more comfortable with the idea. Here's my issue. It's an Ellsworth Roots frame, and I'm running a 1x9 setup. Right now I have an 11-23 cassette and a 34t chainring -- which is a fairly low gearing, so I can spin out 34/11.
I'd like to run something more like a 12-27 / 42t, but the issue is that a 34t is basically the biggest ring that will fit on the inside of the crank spider and have enough clearance between the ring and the chainstays. If I put the 42t on the outside of the spider I end up with a sub-par chain line -- it just doesn't really line up right, and the bike is noisier, has rougher shifting, etc... it's very unsatisfying.
The question: How can I put a larger chain ring on without screwing up my chain line? Is there any way to space out the cassette so that it properly aligns with the chainring when it's on the outside of the crank spider?
Other relevant details: It's a narrow BB, which is one of the reasons that a 34t is the absolute biggest small ring I can get on the inside of the spider. It's a 5 hole FSA crank. Here's a pic of the bike, hopefully it has some useful details: