Originally Posted by pixiehat
Well, the drums are generally a fairly small diameter and close to the center of the rotating mass. I dont think an imballance that close would be that much of an issue but yes, they come ballanced from the manufacturer.
Drums used in the RV industry today are unicast (one piece) and are reasonably well machined.
However, none of them are balanced by the manufacturer, for the sake of balancing.
Note in our photo that we find the heavy spot of the hub and drum, as well as the tire and wheel.
We can say, with certainty, that maybe, just maybe, we "might" find one or two drums, "per year," of the unicast variety, that is actually in balance. Mostly close, within a couple of ounces usually, but certainly "not balanced."