Gas mileage if changing to 35s ?

[TxTruckMan]

Actually, I've studied tires and their affect on MPG for quite a while.  Weight plays a factor, but it's not a huge factor.  Rolling resistance and aerodynamics are the largest contributors.

 

On my 2015 6.2L Denali I ran 22" Bridgestone Alenzas (street tires) 2/3 of the year.  That combo weighed in at something like 88-90 pounds per tire.  I easily got 21/22 mpg on the highway and 16/17 overall average.  I'm a spirited driver.

 

In the winter and when going camping I also had a pair of GMC 18" All-Terrain wheels with Goodyear Duratracs that I'd flip on.  Stock sizes.  Each tire weighed in at a much lower 60 pounds or so.  I would always drop 1-2 MPG with the lighter, off-road tire setup.  Much lighter, but the aggressive tread pattern hurt my MPG somewhat.

 

Now I have a 2021 6.2L AT4 with stock 20" Goodyear Wrangler TrailRunner tires.  I don't know the weight, I assume it's in the 60 pound range, but I know that my mileage sucks balls.  I struggle to get 17/18 mpg on the highway and 14/15 in mixed driving.  It's got to be a combination of the factory lift, aerodynamics, and non-highway tire.

 

Summary - my heaviest tire got the best mileage because it had the best aerodynamics and lowest rolling resistance.

[DustSierra]

Run 275/65/R20 Goodyear Duratracs with 2" level on mine. 34.5" tire that is essentially the most aggressive All-Terrain tire they make A.K.A. the best looking non-mud tire money can buy. Looks considerably more aggressive than Toyo Open Country, K02's, etc. Uber popular tire on other off-road platforms. 

 

Lost about .5-1 mpg over the stock 275/60/R20 Wrangler AT

 

Worth every penny in gas mileage that I lose. Truck looks so much better that I would have gladly done it over again even if I was losing 5x the mileage. 

 

If you are worried about gas mileage, you shouldn't be driving a truck. You could lift your truck 8-10" and throw on 37's and I'm sure you would still be getting 10-12 MPG although you would do much better with a deisel. 

Edited December 3, 2021 by DustSierra

[Supercup]

My past experiece has been 1.5 - 2.0 mpg loss going up 2" - the move up of the front and imact to areo is the biggest impact on mpg.

 

I just sold my 2020 AT4 Carbon Pro - 6.2L - here is a photo of my "life of use" mileage - About 45% of time I was towing - half of that was enclsoed 24' trailer at 7,000 - 10,000 lbs.   Towing mileage in and around S.Cal hills was 6.2-6.5 mpg - got about 8 on flat ground and 4.5 +/- on hills.  I had 2.5" BDS lift with stock Duratracs - great truck - but with 24 gallon tank and poor mileage - had to stop 150 miles or less for gas with enclosed trailer - so just jumped up to HD and diesel motor. 

 

Loved the truck - but was not the right tool for towing! 

 

 

[Spurshot]

On 12/3/2021 at 10:33 AM, TxTruckMan said:

Actually, I've studied tires and their affect on MPG for quite a while.  Weight plays a factor, but it's not a huge factor.  Rolling resistance and aerodynamics are the largest contributors.

 

On my 2015 6.2L Denali I ran 22" Bridgestone Alenzas (street tires) 2/3 of the year.  That combo weighed in at something like 88-90 pounds per tire.  I easily got 21/22 mpg on the highway and 16/17 overall average.  I'm a spirited driver.

 

In the winter and when going camping I also had a pair of GMC 18" All-Terrain wheels with Goodyear Duratracs that I'd flip on.  Stock sizes.  Each tire weighed in at a much lower 60 pounds or so.  I would always drop 1-2 MPG with the lighter, off-road tire setup.  Much lighter, but the aggressive tread pattern hurt my MPG somewhat.

 

Now I have a 2021 6.2L AT4 with stock 20" Goodyear Wrangler TrailRunner tires.  I don't know the weight, I assume it's in the 60 pound range, but I know that my mileage sucks balls.  I struggle to get 17/18 mpg on the highway and 14/15 in mixed driving.  It's got to be a combination of the factory lift, aerodynamics, and non-highway tire.

 

Summary - my heaviest tire got the best mileage because it had the best aerodynamics and lowest rolling resistance.

 

I agree with TxTruckMan.

 

Old thread, but I thought I'd weigh in on the subject of tires and fuel economy.  There's a whole lot of misinformation out there on increased tire weight being the biggest factor for decreasing fuel economy.  It's in every forum I've seen.  Somebody puts a mud tire that's 30 lbs heavier 3" wider and 3" taller than the street tires that were on it, then proclaims that the weight is the culprit for the loss in fuel economy.  Nothing could be further misconstrued. 

 

First, consider that a taller tire has a mechanical disadvantage in leverage to turn the tire.  It's the same thing as using a longer breaker bar to torque a fastener...in reverse.  If you apply force on a breaker bar, it will generate torque on the fastener.  Increase the length of the wrench and apply the same force and the torque on the fastener goes up.  Imagine the radius of the tire is the "wrench" length.  The larger the radius of the tire, the more torque on the axle it will take to move it.  

 

Wider tires generate more resistance to rolling.  Aggressive tread cause more rolling resistance. Weight? that's a long way down the list of influence on fuel economy. 

Edited July 5, 2022 by Spurshot