Joel_980

Hey guys - I have an ecoboost, 4x4 XLT and just ordered BFG all terrain 275/70/18 to put onto my stock tires.

Want to go as big a tire as possible without getting level kit as I hear it kills fuel economy due to more air flowing under front end, angle of nose ect ...

Wondering if ppl can post personal results going from stock into larger tires only,

As well as going from stock to larger tires and level kit,

Anyway to compare fuel economy between those to situations? ... Or is it the same and I should just get a level kit and even larger tires because I won't get any fuel economy with those 33.4" tires anyway (275/70/18)

Joel_980

Not supposed to have smiley shades guy at end of tire numbers, it's an 8 with a ) beside it. U guys are smart ...

And yes I realize the truck isn't supposed to act like a Prius on fuel, but I don't want to kill what it's got in regards to current L/100k

tamnalan

Bigger tires = more rotating mass and a taller vehicle, which will hurt fuel economy.


A lift kit will increase projected frontal area, which will also hurt fuel economy.


Basically the cooler your truck looks, the more fuel you will use...

mixameltFX4

I just got the same tires on my 2010 FX4 and lost about 1 mpg. I think a lot has to do with the weight of the tires. The stock goodyears are less than 40 pounds, I think the BFGs are somewhere around 60. Going to an LT tire is going to hurt your mileage but everything that size and bigger is LT and a lot heaver than the stock tires. I was in the same situation as you not knowing what to get. After I got the tires put on I am happy I just went with the 275/70/18 but I also drive a lot so I didn't want to make the mpgs any worse.

Joel_980

any chance u could post a pic of what your truck looks like with those tires on 18's without level kit!?

Joel_980

Kinda figured all of the above... Just wasn't sure which detail was worse on fuel I guess, the tire or the lift? Or... Both combined --- agreed, the cooler it looks, the worse on fuel.

2003_lightning

Definatly the tires is what does it

TwoTall

I just did the opposite of what you're asking. I had 275/60-20 ATs and 2" level with Bilstein 5100s. First I swapped back to oem shocks to lose the lift and mileage crept up from 17.6-9 to 18.2-6. This week I got rid of the tires for Michelin 275/55-20 (stock 20" size) and reprogrammed tires size. Now I'm back at 20-21 mpg. All these figures are from the factory display during average highway/country road mix. I'm 5.0 2wd screw with 3.31 gear.

Joel_980

Very helpful !! Thnx

mixameltFX4

I don't have one on my computer but I will try to get one tomorrow, if it's not raining.