I've always known my bike frame was too big for me. I got a great deal on the whole bike when I bought it seven years ago. It was an S-Works, probably from the '90s, with all Ultegra gear in great shape.
I find myself on my bike more every week, and the size is beginning to cause me aches, as I'm too stretched out on the bars and have a serious hunch. Getting a new bike or replacing this frame have been on my mind now for months.
All of my components are in okay shape. I'm semi-confident that with some time (and some help) I could move them to a new frame. My concern was that this new frame might not be compatible with my components. Some things, like the shifters, I'm not concerned about. But I am concerned about things like the wheel and bottom bracket.
So my question is, what are the main compatibility issues I could run into with putting old gear on a new bike frame and how can I avoid them?