2011 yukon xl 20" 305's and 2" levle kit gas mileage droped huge?

[jbru167]

i installed a 2"leveing kit and 305 Terra grapplers with 20' wheels and my mileage dropped from 18-19 Hwy to 14-16. My speedo shows 3mph off compared to GPS. How could it drop that much? Will recalibrating my speedo help at all or am i stuck with chip and intake to help?

 

[Donovan]

Recalibrating the speedometer will not fix any thing except the speedometer. Tire size and speedometer reading are not exact anyhow. If you were to look at tire manufactures websites and looked up the same size you would find just as many different measurements as tires. I do not know how a speedometer is calibrated but I do know tire size affects it. You can change your mileage more by driving habits than changing tire size. Miles per gallon is kind of like a speed limit. It's more of a suggestion than rule. I'm sure if your like most of us you like to enjoy driving your truck.

 

[jbru167]

I love the way my truck looks with the 305's just can't beleive that I would loose 3-4 MPG's with this set up...

 

[AZSCTACO]

What's the stock size and what are the new sizes? 305/??/20

 

[InTruckDesign]

You need to get your speedo corrected which will correct the odometer. You probably lost about 1.5-2mpg with the leveling/tires.

 

[felixgun]

Leveling it makes it less aero-dynamic so I could see how the you could lose MPG's from that in itself... get a BB Tune and you can get the speedo issue fixed in two seconds!

 

[domin8]

My loss was, based on the DIC, 1.3 mpg for average fuel economy. I have a 2.25f/1.5r leveling kit and 305/50/20 Nitto Terra Grapplers. The stock size was 275/55/20. Doing the math the speedometer calibration difference was less than 2 rotations per mile. As for the speedo being off from the factory, this is true. About a year ago I found a document to police departments that said the Tahoe speedo can vary +/-2mph at 60mph on a 72° degree day.

 

[Donovan]

My loss was, based on the DIC, 1.3 mpg for average fuel economy. I have a 2.25f/1.5r leveling kit and 305/50/20 Nitto Terra Grapplers. The stock size was 275/55/20. Doing the math the speedometer calibration difference was less than 2 rotations per mile. As for the speedo being off from the factory, this is true. About a year ago I found a document to police departments that said the Tahoe speedo can vary +/-2mph at 60mph on a 72° degree day.

Really I wonder what temp has to do with it? Are you pulling our leg?

 

[felixgun]

I'm guessing the heat/cold makes your tire pressure (psi) change which in turn affects MPG's? Just an educated guess as I have no idea really...

 

[domin8]

I'm not pulling anybodys leg. Do you want the link? It's on gmfleet.com.