That would be excellent data to have, but very few people actually drive their rig on a truck scale when on vacation with their rig loaded with full gas tank, propane, water, groceries, gear, clothing, and people. I have not yet done that myself, but I plan to one day. My rig weighs 9200 pounds according to the Phoenix USA sticker on the kitchen cabinet door. I don't remember if that includes a full tank of gasoline or not. Given it's just my wife and I traveling together, I estimate all the extra weight to be right around 1100 pounds. Maybe I am adding the weight of 55 gallons of gas twice.
- 290 human body weight, my wife and I combined
- 340 fresh water, 40 gallons
- 330 gasoline, 55 gallons
- 140 everything else
1100 total added weight
9200 + 1100 = 10,300 pounds
2007 E350 chassis max weight is 11,500, so I have 1200 pounds of margin (maybe 330 more with gas added twice) which I consider to be comfortable. Adding a 400-500 pound slideout would still be comfortable.
The 2011 E350 chassis is rated 12,500
The 2011 Spinter chassis is rated 11,030
Without more specifics, it appears a Sprinter with a slideout and two people will be right around the max capacity.