2014+ Gas Mileage (MPG) Topic

uptou2bu · November 25, 2015

Anyone notice a difference in fuel mileage when using cruise control vs not using it for highway driving?

I couldn't tell you with the vehicle I have now it's super screwed up, but I have never noticed much of a difference on any of my other vehicles. I've heard it both ways from people. The only real way to tell is drive and do the math.

Anyone notice a difference in fuel mileage when using cruise control vs not using it for highway driving?

I couldn't tell you with the vehicle I have now it's super screwed up, but I have never noticed much of a difference on any of my other vehicles. I've heard it both ways from people. The only real way to tell is drive and do the math.

Anyone notice a difference in fuel mileage when using cruise control vs not using it for highway driving?

I couldn't tell you with the vehicle I have now it's super screwed up, but I have never noticed much of a difference on any of my other vehicles. I've heard it both ways from people. The only real way to tell is drive and do the math.

Anyone notice a difference in fuel mileage when using cruise control vs not using it for highway driving?

I couldn't tell you with the vehicle I have now it's super screwed up, but I have never noticed much of a difference on any of my other vehicles. I've heard it both ways from people. The only real way to tell is drive and do the math.

Anyone notice a difference in fuel mileage when using cruise control vs not using it for highway driving?

I couldn't tell you with the vehicle I have now it's super screwed up, but I have never noticed much of a difference on any of my other vehicles. I've heard it both ways from people. The only real way to tell is drive and do the math.

uptou2bu · November 25, 2015

What size are those tires because if they are 10 ply tires that could pretty much explain the difference, depending on the size...

I know you said "Factory size" But what size are the tires specifically.

LT285-65-18

tyrich88 · November 25, 2015

I had that same size until today and they are taller and wider than stock and dang sure are heavier (Because they're 10ply with 3 ply side walls)
That will make up a big amount of that MPG loss, pretty much all of it. I am fortunate to live in a very flat place, so i dont see a massive loss, but it was still a loss.
I just put some 275/70/18's on, which i think are lighter than what I had on before, and a little taller and narrower. I'll let you know how those do on the freeway this weekend if you'd like. They are bfg ko2's like it looks like you have.

ALSO
The speedometer may be off by about 3% which makes a difference with the MPG calculations as well, because it is calculating off of less mileage than you are actually driving. Not much but that may make up for 1mpg.

Edited November 25, 2015 by tyrich88

Rawyzf · November 25, 2015

LT285-65-18

This is exactly why your MPGS are down. Oversized 10 ply tire.

Make sure the psi is up on these too, probably around 40.

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Rawyzf · November 25, 2015

I had that same size until today and they are taller and wider than stock and dang sure are heavier (Because they're 10ply with 3 ply side walls)

That will make up a big amount of that MPG loss, pretty much all of it. I am fortunate to live in a very flat place, so i dont see a massive loss, but it was still a loss.

I just put some 275/70/18's on, which i think are lighter than what I had on before, and a little taller and narrower. I'll let you know how those do on the freeway this weekend if you'd like. They are bfg ko2's like it looks like you have.

ALSO

The speedometer may be off by about 3% which makes a difference with the MPG calculations as well, because it is calculating off of less mileage than you are actually driving. Not much but that may make up for 1mpg.

What he said too, DIC MPGS is off. Make sure to hand calculate it.

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tyrich88 · November 25, 2015

I ran mine at around 42 up front and 38-40 out back.
I'll let you know how these 275's do and if MPG improves, fingers crossed. but from what you said, your MPG is what I got over 70mph. Hopefully it's better with these new tires, as that may be the solution you need.

Stock size is typically 265/65/18. At least that's what came on my pickup.

Hate for you to have to get rid of the truck, it's beautiful... looks an awful lot like mine ;)

uptou2bu · November 26, 2015

Thanks the dealer will have it back in a couple of days and what ever it takes they will get it fixed or they will keep it. They had the tires on it when I picked it up.

uptou2bu · November 26, 2015

Just thinking , that guy I work with had them put a leveling kit and 20' tires on his and he hasn't had any issues.

mjj · November 26, 2015

Ah so uptou2bu it has larger LT tires. The heavier tires do make some difference. Mine are LT285/70/17 at 44 psi cold, speedometer is corrected and I average in the 18's. Pretty flat driving where I'm at. I still think your mileage seems to low. Hopefully the dealer will figure it out for you.

Rawyzf · November 26, 2015

Ah so uptou2bu it has larger LT tires. The heavier tires do make some difference. Mine are LT285/70/17 at 44 psi cold, speedometer is corrected and I average in the 18's. Pretty flat driving where I'm at. I still think your mileage seems to low. Hopefully the dealer will figure it out for you.

I run the same size LT tire as you. I average about 14 in town and 18 highway. 16 mixed.

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mjj · November 26, 2015

I run the same size LT tire as you. I average about 14 in town and 18 highway. 16 mixed.

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Yeah my daily work commute is almost all open road and highway so I tend to avg on the high end but yeah the cold starts, idling, and city driving will suck mine down probably around 14 too. Nice to get confirmation mine is typical for what it has on it lol. Edited November 26, 2015 by mjj

kennerz · November 28, 2015

The best way to drive these trucks is just not to ever touch the gas. I literally have had the MPG drop on the gauge as I floor it by like one mpg on a 4~ 5 sec burst and it won't come back up for a while after that. I have gotten between 20.5 and 22.5 Hwy and and as low as 14's in traffic driving "normal" with the speed of traffic. On a mostly city & traffic commute I'm seeing 16.5~17 MPG overall. The high I set is 29 on the 50mi ave. So you have to work to get mileage out of these trucks, but they will do it. Tire pressure is really important as well. run at least 40 psi all the time no matter what wheel combo you run. I dropped to 33 psi cold and the mileage went south immediately.

tnchevy · November 28, 2015

40 psi is way too high on the stock P rated tires, especially for the back tire. You are just asking for problems on wet roads not mention the tire wearing out way too fast in the middle.

tyrich88 · November 28, 2015

Just thinking , that guy I work with had them put a leveling kit and 20' tires on his and he hasn't had any issues.

levelling kits from what i have heard, don't make a huge difference. And with new 20" wheels and new tires, it will all depend on the size and weight of the tires.

Like I said before, those 285/65's are taller (which could mean the speedometer is off by a tad) and since they are wide and 10 ply tires vs the factory 4 ply tires, the are a lot heavier. They will be better for pulling and offroad, but they are still heavier, which will hurt the MPG. If you wanted to go with a tire that is just as tall, but a 4 ply (Which will be a lot lighter and still look good) You could go with a 265/70R18 size tire. It stands at 32.6" tall just like the 285/65R18's you have. It's just not a 10 ply size and is not as wide, therefore it's significantly lighter and will not hurt the MPGs like what is on there now. Those BF Goodrich tires that are on there now also come in that size, FYI.

BTW, I still have not gotten to leave town yet as an ice storm came through, but in town the tires feel much better. A lot lighter, better acceleration and MPG is improved, as is the switch into V4 mode. Hoping to get some highway miles in tomorrow and I'll update on those.

Edited November 28, 2015 by tyrich88

uptou2bu · November 28, 2015

I dropped it off with the dealership this morning. The end mileage average was 1581 miles, 16.8 mpg at 95% interstate driving.I stopped the sale so it's actually their truck. I told them they could fix it, sell it,auction it, whatever I didn't really care.