New Tires - Gas Milage Decline!?

Ok, so after 68,000+ miles on my original Firestone 265/65/17 tires that came with the truck, I put a new set of paws on it. The stock tire was good in the rain and rode fine, but it was horrible in snow or mud. No traction.

So I went with a set of BF Goodrich Trail Terrain TA 265/70/17 for my new tires. I like them, like them a lot so far (haven’t used them in snow or mud yet), however it seems my gas mileage has taken a hit. From 20-21 MPG on the stock tires to 17-18 MPG on the new tires.

Is this possible? I guess it is since it’s happening, but geez, never expected it. Can’t imagine a tire change making that much of a difference.

Not really complaining as I do like the new tires and think they will help where I was looking for help. Just wonder why, other than maybe a bit heavier tire?

 

The tires are larger, heavier, and have more rolling resistance than the stock ones. All of that will negatively impact fuel economy.

It's also winter, and winter blend fuel is always worse for MPGs.

Finally, the larger circumference of the larger tire means that you are going further with each full rotation, so your economy is slightly better than the dash will calculate.

 

Tire is 10lbs heavier and a much more aggressive tread pattern, so yes. It is quite possible. And crappy winter gas doesn't help either.

 

I went up a tire size, too, a year ago (stock Goodyear ATs to Mickey Thompson Boss ATs). I lost 2 mpg. No regrets, though!

 

I have the BFG Trail Terrains same size 265/70/17 on my 2019 DCLB and I can get 20-21 highway mpg. They are much lighter and quieter than the E rated KO2s I previously had in 265/70/16 size

 

Incidentally I see no reduced performance in the snow with the Trail Terrains

 

That's not a super aggressive tire. Make sure they are inflated correctly. I keep mine at 32 psi.

 

Welcome to the mpg loss club. The smiles per gal out way the loss IMO All day everyday

 

I have the trail terrains I average 21-23mpg depends on how I drive .gas quality and tire weight does make a difference .also check your tire pressure I run my 33 cold .

 

physics 101

 

bigger more aggressive all terrains get worse gas mileage

 

I went from a light weight highway tire to a size larger MT Baja Boss with 1.5" lift all around and lost 3-4 mpg.

 

I've got a 2021 Sport with Firestone Destinations and will eventually go to 265/70R17s.

Last I checked I was getting roughly 19-21 MPG.

It's my daily driver but work is less than 5 miles from home.

 

based on your other post, it looks like you were considering new wheels and a lift as well. Were these done? They very well can affect MPG's,,,but as mentioned, you went with a larger, heavier tire, so yeah expect reduced efficiency.

 

tire weight is about a 8 pound difference per tire. And you changed size…..have to expect a difference

 

Several things going on here.

The larger tire is making your engine work a little harder. It also means your speedometer is reading a little low. When it says you're doing 65, you're closer to 70. Driving faster reduces fuel mileage. Your odometer is also off which is good news. You're actually driving a little farther on each tank of gas than your odometer says. Once you correct for that it will add about 1/2 mpg back to what you think you're getting. And if you'll slow down about 5 mph that could give you another 1 mpg.

Your old worn-out tires were also about 1 size smaller than when they were new and were giving you incorrect speedometer and odometer readings. With the old tires you were driving a little slower than you thought and slightly less distance per tank. This was giving you slightly optimistic fuel mileage readings. You effectively moved up 2 tire sizes, all tires are one size smaller when near the end of their life than when new. If you factor for this, you were probably getting about 1 mpg less than you thought with your old tires and are getting 1/2-1 mpg better now than you think. You are taking a fuel mileage hit, it's just not as bad as you think.

The more aggressive tire increases rolling resistance which means your truck won't coast as much as before, you'll have to stay on the gas more to keep it moving. That is the biggest difference.

Tire weight alone does not affect fuel mileage. I've gone from a 38 lb tire to a 53 lb tire but stayed with the same size and tread pattern with no change in fuel mileage. A heavier tire takes more power to get moving and you may feel some loss of acceleration. But once moving it doesn't take any more power or fuel to keep them moving.

 

All you have to do is mix 87 and 93 octane gas apparently, then you’ll be getting 26 to 30 miles per gallon. Unfortunately if your truck likes to surf right now be warned.. no longer surfing is one of the side effects.

 

I noticed the same thing when I went from stock to Falken Wildpeaks even though the tire size is essentially the same, but only about a 1 mpg hit. I chalked up to increase rolling resistance from more aggressive tire and a little more weight.

 

That's life...