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Am brand new to airstreams and need to know if I can tow 31ft sovereign with 95 ford e150 full size conversion with the 5.8 liter engine and total weight rating of trailer And van of 12000 lbs.
I suspect that you are going to be in a situation with a fit that is just barely marginal. The empty weight of the '76 Sovereign
without options nor any fluids on-board is: Rear Bath Double - - 5,065 pounds - - - - Rear Bath Twin - - 5,035 pounds - - - - Center Bath Double - - 4,970 - - - Center Bath Twin - - 4,975. Empty hitch weights (without options nor fluids) are: Rear Bath Twin - - 490 pounds - - - Rear Bath Double - - 495 pounds - - - - Center Bath Twin - - 650 pounds - - - Center Bath Double - - 690 pounds.
By the time that options, personal possession, and fluids are added to the coach the likely gross weight would approach 6,200 to 6,600 pounds. If your Ford E150 is like most of the 1/2 ton based vehicles, your trailer tow weight rating with the heavy duty factory towing package likely has a maximum of between 6,000 and 6,800 pounds. While at first glance, this would be within your vans capabilities it does not take into account the weight of passengers, fuel, and cargo carried in the van - - and another thing to keep in mind is that the conversion van is typically somewhat heavier than a similar passenger van (my G20 GMC conversion van was almost 900 pounds heavier than a similar passenger van). My suspcision is that you would either be dangerously close or even over the GCVWR of your vehcile when attached to a '76 Sovereign when loaded for travel.
A general rule of thumb followed by a number of participants here on the Forum is to load a tow vehicle to no more than 80% of its maximum trailer tow rating to provide a cushion for safer towing. You can learn more about the factory weights of Aristream trailers at:
Airstream Trailers Weights and Measures
Good luck with your investigation!
P.S.: One of the reasons that I am a bit skeptical about this combination is my experience with the '64 Overlander (4,440 pounds empty weight/6,100 pounds Gross Weight) with a 1/2 ton Chevrolet Z-71 pickup with the factory heavy duty trailer tow package rated at 6,500 pounds (5.7 Liter V8/3.73 differentials). The truck was simply overwhelmed in the power department by the Overlander - - suspension was not a problem, but power was a constant issue as it couldn't even maintain 55 MPH on the Interstate highways of Southern Illinois - - and it was an absolute disaster on its one and only trip to Colorado where it was down to less than 20 MPH in low gear passing through the Eisenhower tunnel.