clamp length of stems
 

Hi,
I am considering a new stem for my bike. Besides the clamp diameter compatibilities, I was wondering how important is it for the new stem to have the same length for where it clamps onto the steerer tube. This seems like a very important dimension for a stem.

Okay, I guess it's called the clamp height and most are around 40 mm.

Yes, 40 mm is pretty standard although there are a few that are shorter (Thomson comes to mind). If you get one that is shorter than 40 mm, you can add a spacer to compensate.