In addition to carrying capabilties regarding whether to have a single rear axle or dual rear axle another thing to consider is how long the back end will be on the coach. Some of these conversions are just too damn long behind the rear axle and the back end drags over high driveways or unusually crowned streets. Also, nobody mentioned the tremendously improved braking power that is available with a dual axle conversion. I flat tow either a Dodge 1500 pickup (5550 lbs.) or a Ford F-350 pickup (9200 lbs.). Since I originally had Showhauler build my conversion with a single axle and recently added a retractable tag axle, I can tell you from experience that the additional breaking power from that extra axle is a God-send. Of course there are breaking systems available for the towed vehicle. That is probably the right thing to do, but I haven't found it to be necessary now that I have the tag axle.