Well, that's the wheel out...

in message
..net...

guess, or you wouldn't do it

This isn't quite the whole story. The above
description is for what is termed "static wheel
balancing" and stops the up and down movement.
If wheels where infinitely thin this is all
that would be required. The computerised wheel
balancing machines dynamically balance the
wheel. This also corrects for the difference in
weight distribution across the width of the
wheel which results in a side to side movement.
A dynamically balanced wheel will by default be
statically balanced. Small bike wheels and
rears (IMO) don't really require dynamic
balancing. I think bike tyre manufacturers
recommend that wheels above a certain width are
dynamically balanced. I don't have enough
experienced of such matters to say if it can
really make a difference and I often make do
with static balancing myself (i.e. after the
clueless numpties at the tyre fitting place
have screwed up).

HTH

Jim