It's pretty simple, they put the low weight limits on the rack and the saddle bags to try and limit their liability. Extra weight on your bike changes handling so they tell you not to put too much weight on the bike. If they told you that you could put 200 lbs on the rack too many people would do it, then sue HD when they crash.

 

If you need to carry stuff, saddlebags are the way to go. You have space limitations with a luggage rack unless you use a sissy to secure load. I had saddlebags and a luggage rack...heck together they probably weigh more than 11 lbs. My travel tool bag was 5 lbs.

With respect to weight, as previously stated, if you can carry a passenger, then logically you can carry load. Now if you have a passenger, you should use common sense to limit additional load.

Here is a thread of sportster baggers....a lot of ideas on set-up.
https://www.hdforums.com/forum/sport...ur-bagger.html