Originally Posted by melikebikey35

Most new bikes come with 30-40mm of spacers, but I'm a firm believer that you really shouldn't run anything more than 10-15mm. Any more than that and it really starts to effect the handling of the bike (bikes are designed around 0 degrees of spacing). If you need more spacers, then you're better off going with a larger frame (or a different brand/bike).

Handlebar reach is going to have the same effect, handling wise, as stem length...that is, when you are riding in the hoods. Switch to the drops, then handlebars choice will have a larger impact.

Stem angle (if you go with an extreme change, i.e. flipping it) will have the same effect as stacking up the spacers. Which is a lot more noticeable than changing the reach, since it raises your center of gravity, and shifts weight balance towards the rear (both very bad things for handling/stability). So again, if you find yourself needing to flip the stem, you need a different bike. Minor changes in the angle (i.e -7 to -10) can be used to fine tune your position.

Crank length should not be used as a way to alter reach. Crank length is chosen base on rider height/position/hip angles...if you ride in an aggressive position, with open hips, you'll need shorter cranks. In fact, going with longer cranks would require you to increase saddle setback, thus (slightly) increasing reach. Crank length is actually a very tricky, and often overlooked, part of bike fitting.

Originally Posted by sumgy

I have always been able to size my bikes well enough simply through Effective Top Tube length.

Originally Posted by DaveSSS

The 2cm of spacer would put the handlebars in the same position, relative to the center of the bottom bracket. Remember that stack and reach both reference the BB centerline.