I have a 2017 Ram 3500 Tradesman with 4wd and 6.7 Cummins Turbo. My fuel tank is I think 32 gals. My guess is when towing, I will have to stop for fuel EVERY day. I could live with every day and a hal...
My last two Super Duties. I had RDS 90 gallon tanks installed. Got the tank from Northern Tool and my Ford dealer installed them.
I just picked up a new F450. It has a 48 gallon OEM tank. My 90 gallon RDS is scheduled to arrive in about a week. That'll give me about 138 gallons. :)
By the way. Mine is gravity fed with a ball valve. I can leave it wide open or shut it off and use only the stock tank. Never had a problem and would definitely recommend them.