Originally Posted by
Kontact
I don't know if I'm following you. Why would you try to get setback from the stem?
I use the vertical axis off the BB to set setback every time. With a ruler and a plumb line it is quick and easy to do.
After saddle height and setback are done it is much easier to get the bars in place.
The reason I don't follow the stuff you mention about the frame angles is that there aren't any real reference points on the frame that are useful. Even seatpost clamps vary too much in design to use as good references.
This isn't personal and I don't need to prove you wrong.
Then I think where we differ is that I don't assume that people transferring their position from one bike to the other do anything more than measure saddle position from some point on their bars. And most that measure saddle setback will just measure that from the seat tube and not the vertical off the BB. But that's just an assumption I've come to based loosely on things I've read here and seen done in real life.
Maybe I'm wrong to think that way. I just don't assume from the get-go that everyone always does something correctly. But I also don't assume they are doing it wrong if they don't add something that indicates they are doing it wrong. So sometimes like in my first reply to the OP in this thread post was just a bit of info to get the OP thinking about that. They didn't ask any questions about it so I assume they either understood the implications or it wasn't of consequence to them at the moment.