I am planning to purchase a new steel road/cx/touring bike frameset. I want to replace/swap over my components from my 2009 Giant Defy 1. The reason I am making the switch is both for fun and because I want a more versatile bicycle that will allow larger tires and allow attachment of racks and fenders for commuting and light touring.

I am comfortable with swapping the basic components and understand the concepts of sizing for the basic pieces such as stems, bars, seat post, etc. However I am not sure how to determine wheels, drivetrain, and BB. My giant defy 1 has a Shimano 105 drivetrain and I need to be able to swap over some of the drivetrain, BB, and wheels to the new steel bike. I love the 105 set and it has plenty of life left. Swapping over the drive train and wheels will make this project financially viable.

So where do I begin to determine compatibility? How do I know that my derailleurs, cranks, cassettes, and all other parts and pieces will fit properly on my steel frame?

To start a frame I am very interested in is the All-City Space Horse. For learning sake lets use the All-City frameset as the basis for this discussion and I will use what I learn here for comparing other frames in the future. So, what parts from my 2009 Giant Defy 1 can I easily swap over to an All-City Space Horse frameset.

Thanks!