I mean by getting a proper fitting done to your bike. Anybody that know me , they can tell you I can tell you what size I ride st, tt, cs, wb and stem and bars sizes for ROAD AND TRACK BIKES.
I was with a keirin racer and a road racer here in Japan and they was amazed that the short cuts I knew that I could tell the frame size of there bike and the angles. It is Me , I am anal when it comes to stuff like that sometimes.
I learn short cuts and sometimes carry a ruler. You learn this after years of riding and watching pros set up there bikes. Even they after years of riding when they set there bikes up they know what is wrong with it and tape measure comes out and fix the problem.
Get a FIT KIT or Serrotta fitting done.
S/F,
CEYA!