Originally Posted by
RChung
In order to measure stack, you need a horizontal line. That horizontal line passes through the wheel axles, so you need to know something about the fork. In fact, if you have a frame with horizontal rear dropouts, exactly where you put the rear wheel in the dropout can affect the horizontal line so can affect stack and reach (obviously, not very much).
The guy who devised stack and reach verified that if I handed him just a naked frame he wouldn't be able to measure S&R from it.
Ok, but you have HT and ST angles and fork rake. HT and ST angles are dependent on bike being horizontal. If you adjust the horizontal line, then the HT and ST angles would change and move away from the published values, right?
Anyway.. I was working with eg. a Geo chart that looks like the below. Just thinking there's a way to determine the theoretical Stack and Reach with all these numbers, a ruler, some math and a protractor :-) That linked calculator comes really close.
