Benefit of extra fuel tank.

Here here...I went 600 miles yesterday, stopped twice for fuel and somehow managed to get almost the most expensive fuel in those towns....both times!
Long live slip tanks and gravity tanks!

Nice! Although with rising fuel prices, its unfortunately when you need to fill it up!

I remember I had a F150 with the dual gas tanks, I forget how much it held. Back when gas was $1 a gallon it wasn't terrible.

A lot depends on how much you drive. My pickup, unless I'm going out of town, when my stock tank gets down to 1/4 tank, I put in 5 gallons. This will last at least couple weeks of normal use before back to that mark again. Before I hook up, fill the tank. This gives me at least 60% fresh gas. And towing, my little motor does better mileage the 2nd time I fill. Most times, I can run near 300 miles before I get to that 1/4 mark I call MT. Now if I had a extra tank, I would have to be sure it was MT when I get home, or would have more old gas next trip. Then there is the issue of the extra weight. 50 gal, about 400 lbs. How much fuel is needed to haul that weight?

Personally, I would never even think about either replacing a good factory fuel tank with a larger tank or adding an auxiliary tank.

If you want more capacity solely to buy cheaper fuel, it will take one heck of lot of fill-ups to pay back anywhere near the out of pocket cost. If you do it for longer stop intervals, I easily get two bathroom stops out of a tank of fuel with my existing tank.

Adding more fuel at 6-7 pounds per gallon never made any sense to me.

The weight is negligible, both on the truck and in fuel economy. We're talking about F250s and F350s here which get "X MPG, towing or not towing."

Unless your auxiliary tank has its own built in oil well and refinery, though, you still have to fill it up sooner or later. Usually by the time you need to fill up the gas prices have gone up.

I've to to stop and pee, and stretch my legs, and needing fuel every 3hrs works about perfect for me. Here in the southeast, fuel is easy to find, I here out west it can be much further between gas stations. 175-200 miles is my range to find fuel.

I get the pee thing but the larger tanks give you options of driving past the little jammed up small gas stations and finding cheaper gas and easier access. The larger tank is the best mod I've made to my truck.

In the back country in the intermountain west service stations can be few and far between - nice to have the options to drive on.

My f350 with the extra tank will go about 1500mi. Sometimes I have saved as much as $1.00 a gallon so it pays for the extra tank real quick. Gas buddy is my friend. Recently in GA I saved over $1.00 by going to a Kroger 1/2 mi from I-95

I was bucking a big head wind yesterday towing and managed to get 6.5 mpg. Barely made it to my usual fuel stop. I filled 31 gallons in a 32 gallon tank.

Then again, apps like GasBuddy can lead you to the most affordable gas station, which coincidentally, are seldom right off the interstate. Last October, I saved a buck a gallon by driving 1.5 miles further into town, lol where the locals bought their gas.