Gas Pump Hose Preloaded?

[TimTyler]

I like to use high-test in the bike, but I think 90% of the fuel a typical gas station sells is probably the low octane cheap stuff.

So on a pump with one hose and multiple octane selections, does that mean the previous buyer's fuel choice is preloaded in the 12-foot hose + the pump's internal plumbing? How much gas do you think that might be? I wonder how sophisticated those pumps are. I suppose that if they were smarter than I expect, the pump might return the undelivered hose fuel to the source tank after the sale is complete.

[Chaos]

The pumps aint that smart.  You do get a dollop of regular if that's what sitting in the hose.  With a typical 12-16 gallon fill up it would be insignificant,  but may lower your octane a point with a 4 gal  fillup.  Just guessing.

[Scott_]

I would also think that the hose and internal piping would be filled with the last fuel selection dispensed.
as far as length, there is probably close to 8 foot of pipe internal to the dispenser that you can't see behind the panels. I can't say for certain exactly what size it could be, but a guess would be 3/4".