Does tire size effect fuel economy?

[LoveToCamp]

I towed my original 2417, with 13" tires, back from the dealer and got 15.8 mpg. I picked-up my new 2417 with 14" tires a few weeks ago, and, on the same route, same traffic conditions, I got 19 mpg.

Will larger tires normally give better fuel economy, due to a change in rolling resistance? Has anyone else who has put larger tires on, noticed improved fuel economy?

[tentcamper]

With bigger tires you should get less MPG. I think has something else that caused the change. Like speed, outside temp, wind, how full the tank was, etc... I don't relay on one tank to figure out my MPH, I always average over 2 -3 tanks.

[LoveToCamp]

Since I only make that trip when going from dealer to home, I don't have multiple tanks to compare (and, it is only about 75 miles). I was just curious, before we start the real trips in May.

[fourteener]

It would be nice if one of the 'tire experts' would reply, but the theory is,,,,,larger tires roll easier causing a slight increase in fuel economy, while the lift kit added to accept larger tires & the fact that the camper is raised slightly (which equals a bit more wind resistance as it is sticking up above the tow vehicle a bit more) will cause a slight decrease in fuel economy. Lets face it, campers aren't the 'poster children' for shining examples of reduced resistance in wind tunnel test . There is also the fact that slightly larger tires weigh a bit more, and due to centrifugal force this increase in weight has a multiplication factor (dependent upon speed), which causes a bit of a loss in fuel economy.

At the end of the day, it probably isn't really that noticible. Other areas like how much 'stuff' we pack, wet vs dry, accessories, etc. probably have a larger effect on fuel economy than tire size.

[tentcamper]

I would think you should you should get about the same mpg