Math question about stem length and angle
 

Was fitted recently at LBS, among other adjustments, moved saddle forward as I was pretty far back behind the center of the cranks. All the adjustments feel better to me after 2 rides, but I now feel a bit compressed as I am now closer to the bars, especially when on the hoods.

I am thinking that I may need to get a longer stem or one with more of an angle. I am currently using a 90mm 84 degree stem. Obviously going to a 100mm gives me 10 more millimeters of reach.

Does anyone know what the effect of going from a 90mm 84 degree stem to a 90mm 80 degree stem would add to reach?

Thanks.

google is your friend
http://www.habcycles.com/fitting.html
http://www.brightspoke.com/t/bike-stem-calculator.html

Still about 10mm. The angle effect of 4 degrees will have a minor effect on length, and a bigger effect on the bar height. The 80 degree stem drops the bars about 5mm.

To figure all of this, assume a 73 degree head tube angle. The stem angle is 84-73 = 11 (relative to the ground).

The horizontal length of the stem would be cos11 x 90 = 88.3. The height would be sin11 x 90 = 17.2. With an 80 degrees stem it's cos7 x 100 = 99.3 and sin7 x 100 = 12.2. That makes the length difference 11mm and the height change 5mm.

Thanks to all for helping out. Especially DaveSSS for the trig lesson, no wonder I'm in the field of law rather than an engineer...

Wow. Fantastic stem calculators on those links above. Thank you. I had no idea something like this existed. Sure does make figuring out which replacement length/angle stem to get much easier.