After 32K+ miles, I thought I’d share how I interpret the bars on my fuel gauge and how far I can go on a tank.
I’ll start by saying that my riding is fairly consistent and I usually get about 52 mpg indicated on summer (non-oxygenated) fuel. Since I have a 43 tooth rear sprocket, my actual mpg is 7% better because the odometer reads 7% less than actual miles traveled. But for the sake of this discussion, I will use indicated miles.
I normally fill up about halfway up the neck and have estimated that I fit about 5.3 – 5.4 gallons in the tank.
My observations are as follows for each bar of the gauge, assuming 52 mpg:
1st bar will disappear after about 50 miles. 2nd through 4th bars will each take me about 33 miles before they disappear. The 6th bar will take me about 50 more miles. So:
Bar 1 disappears at 50 miles.
Bar 2 disappears at 83 miles.
Bar 3 disappears at 116 miles.
Bar 4 disappears at 150 miles.
Bar 5 disappears at 183 miles.
Bar 6 disappears at 233 miles.
“Flashing” is supposed to be .9 gallons, so I estimate about 45 miles on it. I have never run my tank dry, but I have put more than 5.2 gallons in.
By paying attention to the mileage when each bar disappears, I can judge how I’m doing against my standard 52 mpg, and can project how much further I can go on this tank.
If you back-calculate from the above, you can assume that Bars 1 and 6 are about a gallon each and bars 2-5 are about .6 gallons each. Add those together with .9 gallons for “flashing” and you get 5.3 gallons total.
During the winter months when we have oxygenated gas in California, I immediately notice a drop in mpg by about 10%. I then use 45 miles for bars 1 and 6 and 30 miles for the others. I can almost pinpoint the week when the do the changeover from one formula to the other!
On my cross country trip this summer I found the above formulas to be consistent. When we had a lot of headwinds, the bars disappeared sooner, and when we had tail winds, they lasted longer.
I hope this helps others figure out what the fuel gauge is telling you. Obviously, your mileage may vary.