Originally Posted by
Iride01
But you aren't saying to disregard the seat tube length or nominal size cm or S/M/L.........right?
I can imagine some with really long arms and torsos with short legs not being able to reach the pedals properly on some of the old bikes with horizontal top tube that increase stack by simply increasing the head tube and seat tube length. Even maybe some newer geometry bikes to with sloped top tubes.
Not as critical on sloping or compact frames. Standard frames are when you really need to pay attention to the ST height, especially if you are short.
The geometry of S,M,L,XL can vary from manufacturer. So if one is unfamiliar with stack and reach, the ETT is what you should pay attention to. It will usually jive with manufacturer recommendation....but not always. I could be a Small on one bike and a M on another.