# Why the vertical difference between the right-most point of TT and the left-most (union with ST) is not part of a geometry chart?

One of the things I often look to determine whether a bike fits a specific purpose is that distance mentioned in the title, that is, if you draw a line from the stem to the seat tube, and then you draw a vertical line from the union of both ST and TT to that line, measure such difference.

Maybe it does not provide any meaningful insights, but IMO, when I see a bike with a higher distance at this "metric", it tends to be more focused in AM / Trail, whereas if this distance is shorter, it's often more suitable for XC.

• Are you referring to the difference between "compact" and "regular" frames? – Andrew Henle Feb 19 '19 at 23:29
• So you're measuring the fall of the top tube over its total run? Which could also be presented as the top-tube's "angle from horizontal" ? – Criggie Feb 19 '19 at 23:42
• What are "left" and "right"? Your question would be easier to understand if you used "front" and "rear". – David Richerby Feb 20 '19 at 12:30