Thor Forums

[Jim Jacobs]

The initial "pre-installation" test was a trip to and from Florida on Rt. 95 which is mostly flat. December conditions were dry both ways, i.e. no rain. We tried to be careful with filling the gas tank all the way to the "top", and getting exact measurements, but as you noted, it's difficult. We used "regular" gas at Pilot/Flying J because of the 5 cents discount through Good Sam, and were thankful for the small savings. Filling an 80 gallon tank can be faint inducing. I shudder to think of the cost coming up this summer.

The mileage wasn't exactly 7 mpg, more like 7.07 mpg, and the "after installation" was more like 8.05 mpg. That's still pretty close to the 1 mpg we're suggesting, but we could be wrong for some of the reasons you pointed out.

"Wind" is a huge factor and it is our sense that the trip "south" to Florida met more head wind than the return trip coming "north". However, we didn't keep track of the difference, just the overall mileage for the whole trip.

The second trip was to Florida and back in February, as well as another up to Washington, DC and back, both coming in at just (barely) above 8 mpg. At least the results were consistent even though the conditions were not identical.

However, the Washington journey was done at 60 mph, not 65 mph, so that alone could account for the difference. That said, the terrain is much more hilly, and that's what impressed (and surprised) us most, i.e. that the transmission didn't downshift nearly as much going up inclines, something we were not anticipating. I'm pretty sure that if (when) we upgrade to a newer model someday, if we stay with a gas engine, we'll get the 6 speed transmission which has not only better gear ratios, but apparently stops the insane down shifting through numerous gears when in cruise control at the slightest hint of a hill.

On our Jayco travel trailer, we didn't install Airtabs with the hopes of better mileage (although that is something the company touts, and we were happy enough to accept). We were looking for a way to keep from being blown off the road every time a truck passed us by, which can be quite nerve racking. Airtabs worked much better than we expected for that. The difference was instantly noticeable.

It was mostly, then, for the purpose of steering control that we installed the Airtabs on our "new" (actually used, 2012) MH. Any increases in mileage are incidental, although, much appreciated if true.

We will know more after this summer's long trip to the West Coast and back again. Conditions will range from hilly to flat, valleys to mountains, cool to very hot. Unfortunately, we won't have any "before installation" data to compare with, but I'll update this post along the way. Our current plan is to drive 60 mph under cruise control, but the West is a very big place and we may have to up that to 65 mph just to make it between RV parks where we already have reservations. That small increase in speed could make the entire trip much more costly. Here's hoping Airtabs show some quantifiable benefit.