spokely

I've seen questions similar to this in a number of places, so I created this little tool to do the math for you: http://www.brightspoke.com/t/stem-calculator.html

For example, a 120mm 0 degree rise stem on a 73 degree head tube is here - http://www.brightspoke.com/t/stem-ca...&sl=120&hta=73 - with a reach of ~115 mm and a net 17 degree angle to the ground.

You'd need to play with it a bit, but a 10 degree angle stem (80/100) of the same length (120mm) would give a reach of ~107/119 mm and a net stem angle of 27/7 degrees: http://www.brightspoke.com/t/stem-ca...&sl=120&hta=73

If my math is right then 130 mm is close to what you want: http://www.brightspoke.com/t/stem-ca...&sl=130&hta=73 Actually, 128.8 mm is more exact, but I assume you won't find a stem of that exact length.

This is just a first draft, I'm very interested in any feedback you may have about this tool.