Frozen? Meaning the bearing is actually frozen, or it's just stuck well on the stem?
The latter is the way it is anyway. It's tough to get off. No room for puller fingers/presser plates.
I used a cutoff tool to notch the bearing inner race enough to pry the thing off.
You're not talking about the outer race being stuck in the head, right? You do say 'on the stem'.
Once you get it off, use a piece of pipe as a driver to put the new one one. 1 1/8" diameter (whatever that is in canada!) I think it is. Put the stem in the freezer overnight, whack it once and it'll be perfect!
(Clean the new bearing and regrease it with REAL grease before you do that).
Use the old outer race to seat the new outer race inside the head.
Make sure you ROTATE the stem side to side as you tighten the assembly to spec (not much), and then while holding the stem, loosen the nut, retighten to 'finger tight'
If you're replacing it cuz it was bad, you'll sure enjoy it when it's fixed!!
Guaran-dang-teed! :)