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Main Area => General GS500 Discussion => Topic started by: Groovylonghorn on March 26, 2013, 12:30:19 PM

Title: MPG calculated for 10% error of speed or just straight off speedometer reading?
Post by: Groovylonghorn on March 26, 2013, 12:30:19 PM
I measured 2 tankfulls, 1st run at 80-90mph(72-81 true speed) and being aggressive on the highway with a light headwind of less than 5mph, I got 47MPG. The 2nd run at 70-75mph (63-67 true speed) light on the throttle but with some light passing with a tailwind of 15mph, I got 64MPG. So it seems I got some pretty good mpg at a lower speed but with a good tailwind. Are those getting upwards of 60mpg consistently running at 60-65mph(54-58 true speed)  without figuring the 10% error? It just seems awfully slow for highway speeds. Thanks!
Title: Re: MPG calculated for 10% error of speed or just straight off speedometer reading?
Post by: BockinBboy on March 26, 2013, 12:56:10 PM
My mileage is in my sig...  You can click on it for more details, but basically that's just an average over tankfuls... Each time I fill up, I record the mileage and amount I put in it.  I almost never ride highway only, or city only.  But my average is right around 60.   However, I once reached really high mileage when I was commuting an hour to work, and specifically remember the wind being behind me both directions to work and from work 8 hours later... and I wasn't in any hurry at all.

I will add that a lot of the roads (nearly all, in fact) I ride on are 55 posted speed limit, and I'll ride at 60-65 indicated... Most of these roads are about 5 miles to get to through the city first... so maybe there is some truth to your conclusion there  :dunno_black:

I probably need to update with about 3 or 4 more tankfulls on that sig calculation, as I imagine it has dropped below 60 since I added my R6 throttle tube.

- Bboy
Title: Re: MPG calculated for 10% error of speed or just straight off speedometer reading?
Post by: adidasguy on March 26, 2013, 01:26:34 PM
One tank is not a good measure of MPG. There are variables when filling the tank due to the air space and the filler neck. Sometimes I get a single really high or low reading. It has to be averaged to really know your mileage.

The speedometer is off 10% but the odometer is correct.