I don't think the aluminum hubs themselves are out of balance.
But the blades on the Solo are wide enough near the hub that a difference in plastic density either in the blade itself, or in the plastic portion of the hub can both combine to cause an imbalance.
So perhaps sanding the wide part of the heavier blade will help. People do need to be careful with sanding the hub itself so as not to cause to weaken too much.
But the blades on the Solo are wide enough near the hub that a difference in plastic density either in the blade itself, or in the plastic portion of the hub can both combine to cause an imbalance.
So perhaps sanding the wide part of the heavier blade will help. People do need to be careful with sanding the hub itself so as not to cause to weaken too much.