Poor MPG? Check your speedo

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T

tmils470

10 Year
Joined
Feb 3, 2014
Threads
17
Messages
87
Location
Walnut Creek CA
I have had my lx for about 2 months now and have not been happy with the MPG.
Went on a trip from Bay Area to Reno this weekend and zeroed the Garmin and the car odometer together.
I have over 6.5% error in reading. Speedo is off by more. Idicated 72 was GPS 78mph !

So the take away from this is before you start chasing down mpgs, figure out what the actual miles you driving are.

Yes I have different tires which account for a paper calculated 3% the rest is just speedo error.

Hope this save someone some greif.

BTW I got 16MPG on the mountain tank of gas. I am happy with that.
 
It might be off even more than that. When I calibrated my speedometer with my Garmin, I found that the results were different when going up and down hills versus the flats. Since your trip was a very hilly one, try to find a 10 mile flat stretch and calibrate there. If I remember right, mine is closer to 8% off with 295s.


...via IH8MUD app
 
Good point, i guess the Garmin only measures "flat" travel and can not account for hills. I guess if you think of it like a triangle the Garmin only measures the x axis but we are traveling on the hypotenuse of the triangle.
 
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Just get a Yellow Box and be done with it. Doesn't cost too much and they are pretty simple to install.
 
and when calibrating with a gps you want a straight piece of highway, not a curvy road
 
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