MPG Loss with new Additions, Shame on Me...
Senior Member
Joined: Mar 2013
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From: Houston and College Station, TX
It isn't just the weight of the tires. It's the aerodynamics. A wider tire interferes with the aero. If you do some internet searches, you can find lots of info on how wider tires hurt the fuel economy because of increased aero drag.
I found this out when i went from 235/55x18 tires to 255/55x18 tires on my 2005 Dodge Magnum Hemi. It reduced my interstate mileage buy almost 2 mpg. I have a programmer that enabled me to correct the speedometer. When the 255s were out, 235s will be going back on because the difference in traction is not much.
I found this out when i went from 235/55x18 tires to 255/55x18 tires on my 2005 Dodge Magnum Hemi. It reduced my interstate mileage buy almost 2 mpg. I have a programmer that enabled me to correct the speedometer. When the 255s were out, 235s will be going back on because the difference in traction is not much.
Senior Member
Joined: Aug 2007
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I completely agree. If he put on bigger tires then his speedo and odometer is off throwing off his fuel mileage calc's. He could be off anywhere from 3-5 miles per hour which kills the fuel mileage by odometer by at least 5%.
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Member
Joined: Dec 2013
Posts: 43
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From: Keizer Oregon
Well What a great trick for the dealers, Put 1 size taller tire on all the EB F150 and you will never hear anyone gripe about MPG..I will check the OD in the AM But still would be good to know How far it is off,
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Joined: Dec 2006
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From: Joplin MO
What's more important is the computer uses the speed input for managing the transmission and engine strategies - if the input is off, it's not going to run optimally. THAT is the reason to reflash or reprogram.
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Joined: Dec 2013
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From: Keizer Oregon
Well I had to drive all over the state today, Lots of testing, As For My MPH I used a GPS and it was right on, at every speed, Ask my friend who is a Ford tech and he said from the factory they have a roll out of about 3 MPH so the tire combo was perfect, Now the OD was off about 60 Ft pass the Mile marker every time, Good news, less miles on the truck and longer warranty LOL, Ask him again if they can calibrate it, and he said they can but it only has a setting for 35's not 33's So really not a big deal and in the scope of things I honestly could not tell much difference in MPG Maybe 1 to 1.5 MPG Not enough to make me change my truck, Absolutely love how it turned out and Made it my own!!
