My CX bike is my only road bike and in an effort to actually be able to climb some hills; I want to change my gearing. I really don't have the best climbing abilities without gearing. Before you get into the HTFU comments; I've previoulsly ridden my MTB with road tires and find myself often in my 22 front chainring and 32t cog going up 6% and higher grades; grinding very slowly. At about 13% I have to hike a bike.
My bike is a Fuji Cross Comp with a 36/46 FSA crank and a 12-25 105 cassette. This gives me about 39 gear inches as my lowest; whereas my MTB goes down to about 18. I found that one of the hills I ride often had me at my max on the CX bike - it wasted me. It's only about a half mile long and about a 9% max climb. On my MTB, it was hard but very doable for me. Racing my first races in CX; I've found myself mostly in my 23t cog and my inner chainring. I joke that if I had a single speed I'd use a 36-23!
I've gotten ahold of a 34t FSA chainring and an Ultegra 12-27 cassette. Changing both of these items will bring my gear inches down to about 34. For the rest of the difference to my MTB, that's where my HTFU comes in.
Does anyone see any problems or complications with my idea?
I know my derailleurs will need to be adusted for the changes. I think I should be able to use the same chain as a calculator I found shows only 1 link difference in going from a 25t cog to a 27t with a 46t chainring.