There is ABSOLUTELY no more load on the bearings or studs than without an adapter (assuming the tire is in the same position as drawn). Think about it. Has the load path changed at all?There are two different kinds of adapters. Hub-centric are machined to fit spot on over the lip on the outer edge of the hub. This perfectly centers the adapter and puts the bulk of the weight on the hub itself instead of the studs...which are further from center on the hub. That too could contribute to bearing wear.