ghoyt87

***Title correction*** How many MPG's did you lose after installing larger tires???

Hey guys i just installed 275/70/18s BF Goodrich AT A/T KO's and went from 15 around town to 13.5mpg.

I did have my PCM recalibrated by the dealership too, they said they got it as close as possible. It reads pretty much spot on until you get over 60mpg

so I have lost bout 1 to 2 mpg's since installing the tires.

I can also tell how much heavier these tires are by the way the truck drives...

have you guys noticed the same thing?

12Supercrew

i run 265/70/18s and i noticed about a .5-1mpg loss myself. with winter being here now and the crappy fuel we have, i am not averaging more than 16 on a good day. on long highway trips i can average around 19 but once i hit stoplights its downhill from there...

Haliburton

Increases in tire height and width will increase the rolling mass as well as increase friction which increases drag. Now add a more aggressive tread pattern, the tire will have more rolling resistance. Some of which is offset by your speedometer giving an inaccurate reading. These motors can go so far with minimal change in milage. In reality, if you put on bigger tires, you should get your speedo recalibrated; but who really does. I used my gps to judge how fast I am going and for milage.

shortride

iTrader: (1)

Not only is the size of a tire a factor, how aggressive the tread is will also have an affect on fuel mileage.

Over size tire larger than those tires within factory recommended specifications not only affect fuel mileage but they are also hard on the drivetrain in general. Over size tires makes every work harder.

dakrat

don't forget that it also racks-up the odometer faster than normal...

ghoyt87

the odometer reads less miles than it actually is driven...but i had my PCM Flashed so it is pretty darn close accurate

FI50

... and whatever weight you add, has to be accelerated by your engine before your truck accelerates. Engineers have told me the effect is four times the amount of weight if added to the vehicle itself. So, gaining 60 lbs on the wheels is easily the effect of 240 lbs in the bed, probably more. Hence the reason racers pay mega thousands to save a few ounces of weight in the wheels.

48454

I dropped about 2mpg by adding 2.5" spacer, 18" rims with 295/65/18 duratrac tires. Originally I had the stock 20" rims with scorpions.

PLAT1NUM

lost about 1.5-2 with 33" MTs on my 5.4 screw.
i do believe the dash display is off with avg MPG especially after larger tires.

carryyourbooks

after all that, you forgot to add the weight of my fat......well, you know.