measuring STA

[Miranda]

Thanks for responding... you know that might do it. I'm gonna try to measure my current bike I think to verify I can do it correctly. It is already set up in the trainer atm.

Bike fit... live and learn...
My first road bike was an ill fitting mess. I know from the pro fits I've had that about 73.5degrees-ish is ideal for me. My Orbea Onix dama is a 49cm w-51TT and the STA is 74.5. With the saddle (Terry tri gel) set back at the last "stop" mark, I achieve a good KOP. Many brands of smaller size bikes the STA just gets too steep, like 75-76degrees. I know if the STA is any steeper than my Orbea, I will be past the "stop mark" and need a set back set post... which starts to throw off your center of gravity etc. I can also ride a guys size 48cm if the TT is not TOO long. I'm all torso, and short legs build. Which we all know the more you hafta push back the seat, the TT virtually gets longer and longer. Gheez, it's really hard to find smaller bikes with slacker STAs!

This bike is going to be like a "back up bike" to my good carbon roadie. Looking for good used, or lower end new bici price range.

EDIT ADD: Just going to throw this in here if someone has any brilliant brainstorms on other choices of bikes that work geometry wise... my "if I'm buying new" choices are:
1) a 2nd Orbea 49cm dama Aqua T23 (comes either flat or drop bar same price) geo size 49cm ST43 TT51
HT110 STA74.5 http://www.orbea.com/us-us/bicis/mod...ama_flat_t23/#
2) Cannodale women's Sunapse alloy 7 geo size 48cm ST44 TT51 HT113 STA74.5 http://www.cannondale.com/bikes/wome...s-alloy-7-sora
3) REI brand flat bar roadie Novara women's Express XX size "extra small" geo ST43 TT53.5 STA http://www.rei.com/product/807244
*while the TT is longer on this bike, it's about like my hard trail mtb, Trek wsd 4300 size 16" (ST40.7) TT53.4 STA74... I think it works ok because I'm not stretching out to the hoods or drops like on a roadie*

Just thinking "out loud" here ... the challenge in directly measuring the angle is turning those cylinders of the tubes into straight lines that you can line anything up on accurately.

What about an indirect method using a plumb line, a level and a couple of rulers? What I might do is first set the seatpost so that it's the right height for you. Set the bike in a trainer (with the front and rear wheels level), take the plumb line from the center of the seatpost clamp and measure horizontally from the center of the BB to the plumb line. Would that give you the fit information you need?