Originally Posted by
DOOM_NX
I don't know, that bit confuses me, as well. Giant doesn't state if the number refers to the effective or virtual top tube length. That's why I chose compare the head tube length.
Bikes with sloping top tubes will commonly have both measurements and when only one is given it is effective top tube not actual.
A nice non-subjective test is the wheelbase. measure from front skewer to the back with the bars straight and there you can also get a good indication.