We have a 2010 Edge Limited with upgraded (18-inch) wheels
and tires. I wonder what, if any, effect this upgrade has on the
odometer and MPG calculator readings.
The reason for asking is the manual calculation of MPG (miles
driven per the odometer divided by fuel used at the pump is
always less than the generous MPG displayed. Yes, both were
reset at fill up
The Edge does not even come close to the MPG on the EPA
sheet Ford used to sell the vehicle. It said 25 MPG highway
and 18 City. We get 20 Highway and at best 16 in city.
Could the wheel/tire upgrade effect the numbers?
Two things you can do:
1) When you are driving down the highway or road, and there is one of
those mounted RADARs that show your speed (to encourage people to stick
to the speed limit), compare your speed against the displayed speed for
2) When you are driving on a highway, compare the miles driven on the
highway according to the mile markers to the miles that pass by
according to the odometer. They should be close.
Have you tried checking the accuracy of the speedometer and odometer on
an open highway with mileposts? To check the speedometer with a
stopwatch, time how long it takes to travel exactly one mile. Then
divide 3600 by the number of seconds elapsed to determine your speed. A
few examples: 60 seconds = 60 mph, 50 seconds = 72 mph.
I borrowed a GPS unit from a friend for recent trip and it displays speed
that was close to the speedometer. I really don't know how to check the
Ford MPG reading. It is a average thing from the last reset. We filled
up and drove for about 100 miles non stop n the interstate and then
filled up. The miles/fuel used was less than on the Ford display. The
Ford display is generous to satisfy owners.
The purpose of my posting was to find out if Ford does anything in the
computer system to compensate for different size wheels and tires.
Yes.. the wheel/tire size is part of the programmable parameters in the
module that collects vehicle speed sense. Depending on year and model, this
could be (but not limited to) the PCM or the ABS module.
A few years ago, Ford would let us play with revs per mile or tire size to
pretty much customize the speedo. These past few years, Ford has taken away
that ability and has limited our choices to tire sizes available from the
So.. what can you do? You can visit the websites of the tire manufacturers
involved (both the original tires and the replacement tires) and compared
the roll out of the tires. This will be expressed as "revs per mile" and
will give you an indication of how close your replacements are to original.
To access the programmable parameters, you will need a scan tool capable of
accessing proprietary modules and capable of bidirectional communications.
Go to this site and put in the stock size tire and the new size.
It will give you all the info. Distances covered per revoluion,
differences in MPH, etc.
I used it to re-calibrate my speedo. I re-calibrated with my programmer....
Good web page but I have no idea what wheel/tire size Ford used at the
factory for the computer calibration. The oversized wheels and tires
came with the car and were PRICED separate on the sticker so I assume
the computer was programmed for correct wheels and tires.
The bottom line is the Edge uses more fuel than we expected. Don't
believe the Ford/EPA stickers on new cars. Take the lowest extreme
number listed and you will be close.
I called Ford after two tanks of fuel and they told me I would be
charged by the dealer to check the factory calibration settings. So
much for customer satisfaction and TQM.
The Edge is a good vehicle it just uses more fuel than we expected.
Well, it has nothing to do with customer satisfaction... and everything to
do with not looking....
The VIN decal will list the size of the tires installed at the factory. The
speedo calibration will be for those factory installed tires and the factory
final drive ratio... Somebody else installed non-stock wheels and tires...
somebody else made profit on those wheels and tires.... why is it now the
dealers "duty" to do stuff for free?
I'm not trying to look like a dork here but I see the same stuff over and
over and over. I could spend my entire day doing free stuff... free advice -
a free scan - a free reproduction from the manual.... free-free-free. At the
end of the day, I will have a hard time helping my wife find a recipe for
warm and fuzzy feelings.
When I had my own store I would joke that people felt that I should buy wire
by the roll so I could give it away for free by the foot.
Now... as one final thought... I understand that you bought a car and didn't
peruse the VIN decal and therefore didn't compare it to the tag in the
corner of the windshield?
WTF are you talking about? Ford offers a "base" tire and one or more
optional tires. Each vehicle will be programmed for the tire/wheel combo it
ships with. There is no "compensate".
FWIW, if you had seen what info the scan tool offers, you wouldn't have egg
on your face.
I sincerely doubt any re-calibration was done. The difference in
circumference between your tires and the stock(base) tires is about 1.2".
The difference in fuel consumption would be well within the EPA estimate as
posted on the sticker. The operative word here is "estimate". The EPA does
not guarantee that you will get exactly their estimate. The miniscule lower
mpg you are getting is more than likely caused by the motor working harder
to turn the taller wider tires.
In addition to verifying speed, are you able to verify distance with the
The MPG meters are never really accurate. They rely on guessing how much
gas is being burned, but the energy availble (which varies slightly) and
others factors could throw it off.
If there is a no_junk in my address, please REMOVE it before replying!
All junk mail senders will be prosecuted to the fullest extent of the
I was able to verify GPS reported mileage against odometer reported
mileage on my Honda within a couple of tenths of a mile up to 100 miles.
At that point the GPS drops the 10ths, so the matchup becomes less
The GPS mileage may become inaccurate if you travel into any area where
satellite coverage isn't continuous, in coincidence with some roads that
aren't straight, as the GPS will estimate that your travel is still in the
same speed and direction for a while after loss of signal.
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5
Your mileage is in line with the mileage reported by Consumer Reports:
CR's overall mileage, mpg 16
CR's city/highway, mpg 11 / 26
Measured fuel usage on CR's 150-mile test trip of mixed driving, mpg 20
The Edge is a large heavy vehicle with a large frontal area (i.e., lots of
According to CR other vehicles in this class similar in size get similar
A vehicle of this size was probably not the best choice if fuel economy is a
primary concern, Both the CR-V and Highlander get better mileage. When we
were shopping for a new vehicle for my Mother, we looked at the Edge,
Highlander, and CR-V. For her we decided on a Highlander (4 cylinder model).
It was a little more expensive that a better equipped Edge (V6 SEL) after
incentives, but also suited her better and gets better gas mileage. Of the
three I actually preferred the Edge (better driving position, much better
performance, and likely less expensive to maintain, etc.), but the vehicle
was for an older lady who mostly drives 30 miles a week. The Highlander jsut
seemed a better fit for Her.
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