SamYO wrote:
Bump anyone happen to know?
Another question does a steep frame need the same setback measurement to get the same positions?
I don't know the answer for you particular bikes.
This is my technique (not a fitter or expert).
I have three bikes (TT, road, track) and try to set them up as similarly as possible w.r.t. saddle position and height. I use the same saddle on all three.
I use two measurements. I measure from the center of the crank spindle along the seat tube to where the seat tube would intersect the top of the saddle. That's classic saddle height. Though some people measure to the rail. Or the middle of the saddle. Whatever, just be consistent and be aware that you if you change saddles they can differ in rail-to-top distance.
Then I take a plumb bob and drop it off the tip of the saddle and measure the horizontal distance from the plumb-bob line to the center of the spindle. That's classic "saddle set back."
Just be aware that if you change one, the other can change slightly, so if you're adjusting, it can take a few iterations to really zero in on the exact replication of another bike.
From those two numbers you can calculate your effective STA given your actual saddle position. But you don't really need to calculate the angle unless you're just curious.
I can't quite replicate across all 3 bikes. My road and TT bikes I can get very close (Felt DA and Felt AR). My track bike is just too "relaxed" to get there even with the saddle slammed forward. So I live with it, for now.