Oh yeah, do you have a service manual? There is a special torque sequence for the nuts, and since you were using channel locks before makes me think you may have not been too exact on that in the past. ;)
54mm=2.125 inches, or 2 1/8".
The 1/2" drive hole on my stamped one is actually deforming, pretty soon I'll have to go out and buy a sears one as well. If you don't already have any, get some ratcheting wrenches while you're there, they are the shiznit. Pricey, but sometimes irreplaceable.
I wouldn't buy one of the stamped steel ones except for occasional trail use. That said, thats what I use. :slap:
They wear out very fast, go to sears, etc and buy a good one. Just make sure the walls are not too thick so it will still fit inside the hub.