Harley on a 5er

We have a 2010 36tk3 DRV that we purchased new. When we had it built we had the factory beef up the frame for the added weight as we anticipated carrying our Road King on the back.The factory at the time authorized this. We have the 17.5 wheels and a 8k lb axles. We have learned a few things since our purchase and have not carried the bike on the back nor will we be doing that. The factory did authorize it then but they no longer recommend it. Not just because of the weight but due to the severe jostling that occurs. This is why Excel allows it in their 32 ft or less models. At least we have a beefed up frame...ha. Also our current belief is that 800 lbs on the back will over-load the axles, but not the tires. Like I said we have learned a few things. We currently sit with about 7300 lbs give or take on each of our axles. The tires are rated for 4800 lbs ea. We will be using the Blue-Ox Sport Carrier ll. It is like a swivel wheel but smaller. It is only 4 ft deep and 7' wide. These dimensions will help keep the swing out to a minimum. It has a carrying capacity of 1000 lbs. It has two tires but they are side by side. We currently tow doubles with the Harley but prefer to have the option to back up.