Adapters, while an easy change-over to create a pseudo-dually, I have heard opinion that there could be other or different wear factors because the axle tube dimension (track/ width) is longer on the dually where as the SRW has a narrower width.
IIRC it had something to do with axle bearing placement relative to the outer edge: a longer moment is created on the bearings by the fact the force (CL of wheels) is further away when compared to the factory dually axle track.
Any opinion on that? I had thought briefly of doing the conversion on my SRW 3500 until that thesis was presented to me.