Effect of tires on gas mileage

aatk · Nov 8, 2021

So right at 20k those awful stock Goodyear 22s gave up the ghost. I swapped them for a set of Firestone AT/2s - I wanted something that could handle more than an inch of snow and these are rated to do so.

What I didn’t consider was the effect on gas mileage. I‘ve done 5k on them and it’s consistently 2mpg less with the new tires. I did two long trips to roughly the same area along the same highways and it went from 19.5mpg to 17.5mpg just with a change of tire.

I never saw that much difference before on a tire change. Anyone else see similar results?

Moose2 · Nov 8, 2021

Sometimes. Weight And size of tire matters. Bigger or heavier tires take more juice to turn.

retired · Nov 8, 2021

did you get the same size? if new ones are taller they will show less miles than actually driven so that woud make your mpg seem less when in fact it might not be.

LouM · Nov 8, 2021

Even the same size and weight a more aggressive tread pattern will get less mileage then a highway tire,
it's been that way for many decads even back to bias ply and belted tires.

LugsLeadOut84 · Nov 8, 2021

That's normal. An A/T tire is heavier and the tread pattern which makes it suitable as an A/T tire is less economical. It's described as "rolling resistance". I'm not consumed with MPG and don't pay exact attention to it, but I definitely noticed the EVIC displaying slightly less MPG (1-2) than with the stock tires. But remember, you wanted something that could handle more than an inch of snow. You got it but have to give and take a little.

You have a truck. If you were THAT concerned with MPG you would've bought a Prius, right?
Enjoy the truck and better tires....

.

mtnrider · Nov 8, 2021

2mpg drop seems excessive going to that Firestone? (assuming you didn't change sizes). I'd consider that model a street tire and it's not an aggressive tread by any means. I'm surprised they even call it an "AT". Maybe it's more aggressive in person then the picture look though?

.

Phirebeard · Nov 8, 2021

Are they a heavier ply than the OE? Check tire pressure? I have the FS AT/2s on my truck. They're more aggressive in person, but definitely geared more towards highway than dirt with the center tread. I'd call them more like a highway/AT hybrid lol. They do well in the snow.

BWL · Nov 8, 2021

I found the same with my very heavy nitto ridge grapplers vs my snow tires. If I didn't need a heavier tire I'd probably run Michelin LTX.

aatk · Nov 8, 2021

To answer a couple of the questions.

Of course same size.
Tire pressure is correct.
Don’t really care about the mileage.

Was surprised a set of tires could make >10% difference on mileage. It’s hilly where I live, so I’m getting 12s around town vs the 14s I was on the other set. That’s down in Land Rover territory...

zeus2120 · Nov 9, 2021

aatk said:
So right at 20k those awful stock Goodyear 22s gave up the ghost. I swapped them for a set of Firestone AT/2s - I wanted something that could handle more than an inch of snow and these are rated to do so.

What I didn’t consider was the effect on gas mileage. I‘ve done 5k on them and it’s consistently 2mpg less with the new tires. I did two long trips to roughly the same area along the same highways and it went from 19.5mpg to 17.5mpg just with a change of tire.

I never saw that much difference before on a tire change. Anyone else see similar results?

I too swapped my Goodyears around 20k for Firestone AT/2s. Same thing -- lost 2 mpg. Love the tires though. Way way way better in rain and snow.

Rlaf75 · Nov 9, 2021

Assuming the tires are the same size, tread pattern/aggressiveness, load range and air pressure will have an effect on gas mileage. It is a pickup truck so you wont break any fuel efficiency records to begin with

LeeD · Nov 11, 2021

Also don’t forget to consider that the gas might have changed from the summer blend to the winter blend.

farout75 · Nov 11, 2021

I noticed a mpg change going from a 4 ply to and 8 ply tire. I am not sure if I will do that again. I get just as much ware and mile either way a 4 ply tire are a good deal cheaper. I do not tow so that's why I have no issues with a 4 ply tire.

TomB 1269 · Nov 11, 2021

I believe you are seeing 2 effects here, weight and rolling resistance. The rolling resistance could be confirmed by checking the ratings of both tire in general. However, having owned the same tire on a different truck I can tell you that the ones on our truck came from the factor with less tread depth / material. I have never see a tire wear to the point of need replacement (based on wear bars on tire) at 24000 miles. I have seen tire on badly aligned vehicles, etc. but a brand new truck with 24000 miles should not "REQUIRE" new tires. My truck comes off lease in March. I am due for inspection in March. I have a strong suspicion based on what I am seeing now that I will be required to replace all 4 to pass inspection (OR FIGHT WITH TECH OF 1/32 OF AN INCH)
IMO it is further EPA conformance. In order to get a minimal amount of increased fuel mileage they put on "lighter" tire with less tread.

It looks as if you maybe the one that can most likely prove, or at least make than an anecdotal speculation to this.

Would be great to here what if any difference you find in the rolling resistance rating for the new tires vs the original.

rvance · Nov 11, 2021

The factory tires are made for gas mileage and nothing else. Every decent tire will bring down your gas mileage.

Ram 1970 · Nov 12, 2021

It's been said already: Rolling resistance and tread pattern are the two main contributing factors.

Tire design has been an ongoing improvement for a long long time now (since at least the early '50s). Fuel economy is one of the main reasons why. An A/T tire will drop your mpg when switching from an H/T tire.

You can, of course, verify that the tires do have the recommended air pressure in them. But most likely you are gonna have to deal with the loss of fuel economy.

Carlo Santin · Nov 12, 2021

I'll happily give up a bit of gas mileage for a better, safer tire. I have the Falcon Wildpeaks A/T winter rated tire on my 1500. They are terrific in the winter and good in the rain. I'm sure I could get better gas mileage with a dedicated summer tire but I don't care. The Wildpeaks are great and I don't need to change over in winter.

seabrook · Nov 12, 2021

rvance said:
The factory tires are made for gas mileage and nothing else. Every decent tire will bring down your gas mileage.

thats just what i was about to post. My goodyear SRAs (oneyears) blew out at i think 28k miles (rear tire blew) they are garbage tires.

my wife's Cayenne was chewing through a set of 21" Pirelli's after 11k miles before i found continental extreme contact 21's you get a whopping 35k miles out of them LOL

TestPilot57 · Nov 12, 2021

aatk said:
So right at 20k those awful stock Goodyear 22s gave up the ghost. I swapped them for a set of Firestone AT/2s - I wanted something that could handle more than an inch of snow and these are rated to do so.

What I didn’t consider was the effect on gas mileage. I‘ve done 5k on them and it’s consistently 2mpg less with the new tires. I did two long trips to roughly the same area along the same highways and it went from 19.5mpg to 17.5mpg just with a change of tire.

I never saw that much difference before on a tire change. Anyone else see similar results?

I didn't read all the responses, so this is an unbiased response.

Most "1/2 ton" trucks sold today (regardless of mfr) are using "P" rated tires, IOW Passenger (car) tires. They have low rolling resistance and lower load ranges (though still within the rating of the vehicle). They do this for two reasons - they're cheaper, and provide better MPG, which helps them with CAFE. And since 98% of 1/2 ton trucks are used as nothing more than a sedan without a trunk lid*, customers are happier with the quieter and smoother ride. Win-win except for those that want to use their truck as a truck.

*frankly, mine is too, 98% of the time. Although I did add an almost-watertight "trunk lid"...

TestPilot57 · Nov 12, 2021

LeeD said:
Also don’t forget to consider that the gas might have changed from the summer blend to the winter blend.

That used to be more of a factor around here (VT), but as far as I know, almost all gas around here is 10% ethanol (lower MPG) year round. I run ethanol free (generally only available as 91 octane) in all our vehicles and utility engines because I don't like the potential complications from accumulating water in my fuel. Now, if I was looking for maximum power with forced induction, I would take the drop in MPG...

Effect of tires on gas mileage

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