Here's another item. Even the slightest headwind makes a difference. Often when we ride, we don't notice the prevailing wind much. But riding in two different directions on the same highway has netted me a difference of 10 mpg in the hybrid (again... I use this for an example because of the accuracy of its fuel mileage gauge) Just for the hoot of it, it looks like this:
So when I'm in the car, I find myself checking the exact mileage I get during all kinds of different conditions. Most of the time: traveling in different directions on a level road at the same speeds nets EXACTLY the same mileage. And though all this checking tells me nothing about the FJR, I learn plenty about just WHAT causes changes in mileage. What have I've learned? A vehicle gets slightly different mileages at any speed based on two factors that I can't gauge very well most of the time. First, as I said, is wind. Sometimes I'm heading into a slight headwind... I'll notice my "normal" gas mileage is running about 3 mpg low. Then I'll turn around, head back the other way, and sure enough, traveling downwind, the mileage is 3-5 mpg higher than usual. The only difference I can see: the wind. Other times I'll be traveling up a slight incline. Mileage is running lower than usual. Again, I'll turn around, head back the other way, and note that the mileage is higher than usual. The only difference I can see: the slight incline. Most drivers don't notice changes in mileage due to things like this. But in the hybrid, I find myself watching it all the time. Here's another factor: Mileage changes based on temperature. It it's in the 40's - mileage runs maybe 3 mpg below what I get in the 70's. Now here's the deal: Sometimes these factors add up. For example, traveling up a slight incline, with a slight headwind, at cooler temps, could easily add up to 10 mpg below the average, and for me, unless I've got access to equipment that can gauge changing wind or altitude, it's a guessing game. But what I DO NOTE is the huge change in mileage. WHY is sometimes a combination of many things, none of which have anything to do with the performance of my vehicle. I'm guessing that these same factors might be the reason that several of us have noted huge mileage differences as we check it under varied conditions.
However, there is one thing that's always constant. Once I reach about 50, the faster I go, the poorer the mileage. Below that, not much difference at all. At 50 I might get 47 mpg. At 85... 30 mpg or so. That's a huge difference. And it's caused by only one thing: wind resistance.
Gary
