Right now I'm looking at lower end bikes, let's just say, under 1000 bucks for sake of argument. And I tend to be a fairly analytical person, so I'm playing around with the published frame dimensions from various makers while I wait for the store to call me when a particular bike-of-interest arrives. It seems that there is actually relatively little variation in geometry among frames. For instance I've looked at three frame sizes across one brand, and they all have the same Reach within a few mm, likewise for my two old bikes from the early 80s.

This gets me thinking. My body is attached to the bike in three places: Seat, crank, and bars. Hypothetically, relationship between those three points determines, to a good approximation, the fit of the bike. The seat can be moved up and down, and front to back, by a fair amount. This leaves the Reach and maybe the stack height as the only two real variables.

Unless I find a particular bike that's remarkably different from the others (and the salesmen have told me that bikes within a category are all sized similarly), there's not much to fit on a bike without being able to vary something else, i.e., "something has to give," and it's the stem. Maybe hybrids have a hinged stem for this reason. If so, then my strategy for fitting a bike is to get within the ballpark on standover height, take what I get for Reach, and budget for installing a different stem.

Does this sound reasonable? Or am I either 1) missing something major, or 2) over-thinking it? Is fit a reason to buy a more expensive bike, if I can correct reasonable fit issues with a different stem?