This is my issue I have a set of Firestone airbags with The 2.5in leveling kit with 35in trail grappler. I haul a 36ft toyhauler weighing 12k loaded with a hitch weight of 1340lbs. And with 75psi in the air bags it still sagging even tho the helper Springs aren't even being used.
I plan on buying a buying a sxs and putting it in my truck bed. I can only imagine having 1300lbs in the bed and towing the trailer.
My question is should I go back to stick size tires and take the leveling kit off? Or do I have other options? Maybe thicker Springs or add a leaf?
You should look at the StableLoad suspension upgrade product for what you're describing. Many people using airbags for leveling are also using these for added stability and handling. It will pre-activate your factory leaf spring and reduce sway and sag. It is easy to install, and you can disengage in seconds when not towing and hauling putting your factory suspension back to your stock ride. StableLoads
Here're some FTE links for in use reviews: https://www.ford-trucks.com/forums/12...d-install.html
Just to verify does your truck have the lower leaf spring overloads or the upper overloads?
With both types, we generally recommend starting with the Quick Disconnect StableLoads for the lower overloads Part # A7310 or #A7311(comes with the drill kit, if needed). It looks like your model year comes with the hole already in the lower leaf spring.
Here's a link to the FAQ page which goes over the difference and best choice for your truck. StableLoad FAQ
The lift is going to depend on the weight you are carrying and other factors?
I have them on my F350 with a 4000lb camper and they give me a couple more inches of lift and I can reduce my airbag pressure to 30lb from 70lb. Check out the Truck U video and it shows a before and after as well. I can't say for sure what the actual lift dimensions for your application would be, but I am confident you will realize a much more stable ride. Hope this helps and I am including the link below to the Truck U video page. Let me know if you have any other questions. StableLoad - Truck U video