Rb0553

I have a 2014 F-150 SCAB, 4X4, 5.0L 3.73 gears, no mods. Back in March I replaced my tires. I went from Michelins to Generals. The specs from Tire Rack were identical as to tire diameter, revolutions per mile etc. Right around the same time I noticed that my gas mileage started sucking. Without going into specifics as to the MPG, I have calculated the loss to be 19.05 %. WTF??? I changed the air filter, I even inflated the new tires to 5lbs per tire over the specs from Ford for my tire size. The truck is throwing no codes. My scan tool shows no codes or malfunctions. In speaking with the service Mgr. at the Ford store (who is a friend) he says this could be real difficult to track down, and I agree. He also said he would give me a free hour of tech. time so they could check my throttle body to see if there is any problem with that. He also spoke about using cheap gas, but I was getting the better and worse mileage on the same cheap gas. I will be having the throttle body checked out, but outside of that, I don't know what else I could be looking for. I had the truck serviced recently where they measured pad wear etc. and if my pads were dragging I would think they would have caught that. So my fellow forum friends...what do you think may be going on? Thank you for any input.

Siber Express

The Generals wider, I lost mileage when I went to the 305's even though they were the same height they were still wider and had more rolling resistance.

marshallr

Rolling resistance. I'm betting the General tires have a more aggressive off road tread. Even in the same size and tire weight a more aggressive tread will generally cost about 2 mpg. From 18-16 mpg is typical. Going to a wider tire adds to the rolling resistance even if they are the same diameter.

aandrews109

I stayed with the factory size, 275/65 R18's on my '13 with Ecoboost. Went from Goodyear All Terrains w/ Kevlar to E-Rated BFG KO2's and lost between 1 to 1.5 mpg. BFGs are quite a bit heavier tire.

Rb0553

The Michelins are 8.1 tread width, the Generals are 8.2 tread width. And that will cause a 19.05% loss in mileage? In more direct terms I went from 21-22 highway MPG, to high 16s highway mileage. Is that actually possible? To be only the tire change? I supplied the tire info as the problem did occur around the same time, but 1 tenth of 1 inch could cost me about 5 MPG? And just so I can be providing all info I went from Michelin Ltx At/2, to a General A/TX. Now to be clear, I am throwing this question out to the forum because I am baffled. I am just wondering due to the HUGE loss of MPG, if the tire part could merely be a coincidence due to the extreme change in mileage, with such a small difference in tires. Again, wide open for hearing the comments.

M0RRIS

Check your air pressure. Maybe it’s low?

Rb0553

Thanks Morris, I went 5lbs over Ford specs for that size tire to see if it would help....but nada. Truck sticker says for that tire 35lbs. and I went to 40.

Rb0553

The Generals are 2lbs heavier.....but I lost about 5 mpg highway.

M0RRIS

The grabber looks like bfg, the Michelin looks more street worthy. Could be the reason why

Rb0553

Morris, I hope you don't feel like I'm splitting hairs here. But I did see that you said it could account for 2 mpg. After seeing the tires like it looks like you have, are you saying I could lose 5 mpg? And if so...boy did I pick the wrong tires. I had no idea. On Tire rack, they have a better rating from buyers in about all categories. But I of course didn't see anything in the comparisons that would have alerted me to this. If this is the reason...I'm bummed!