Tires and MPG

Brianj5600

Brianj5600

TJ Expert
Joined
Jul 4, 2018
Messages
3,359
Location
Middle Tennessee
I bought my TJ about 5 years ago and always checked MPG. It is a 4.0, 42rle, 5.38 gears for the last 3 years and 4.10s before and MPG never changed. It had Dick Cepek mud 35s from the previos owner, then M/T Deegan 38s the same size. Every time I bought gas MPG was 10 +/- .2.

I now have the same size Cooper STT pros, which I really like. The bonus is now I get 12.5-13.0 MPG. Anyone notice MPG change in fuel mileage with only the brand of tire change?
 
Brianj5600 said:
I bought my TJ about 5 years ago and always checked MPG. It is a 4.0, 42rle, 5.38 gears for the last 3 years and 4.10s before and MPG never changed. It had Dick Cepek mud 35s from the previos owner, then M/T Deegan 38s the same size. Every time I bought gas MPG was 10 +/- .2.

I now have the same size Cooper STT pros, which I really like. The bonus is now I get 12.5-13.0 MPG. Anyone notice MPG change in fuel mileage with only the brand of tire change?
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Tires can really change MPG based on rolling resistance and construction. I went from Firestone AT2 (garbage tire) to BFG KO2 and lost 1 MPG in my Ram 2500. I gained a lot of traction and hydroplaning resistance. Everything with tires is a give and take. I got stuck on a flat grass field with the Firestones, had to use 4wd to pull my boat up the ramp. KO2 fixed that but cost me some fuel.

The STT Pro is a newer product compared to the Deegan and the DC. I could see it having better tech for rolling resistance.

You should see what going from a 37" BFG to a 43" MT Pro XS does for MPG. I think my Jeep gets 5mpg now, not kidding.
 
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I’m not sure. Last time I noticed a change in mpg I changed tire size and tire type. I assumed the change in mpg was due to the tire size going from 33-35” and my gearing being less than adequate. Good question.

P.s. I believe the Cooper STT Pro is a hybrid tire, and not a full MT. I know I loved my set. I’ll be going back to Cooper next time.
 
JMT said:
I’m not sure. Last time I noticed a change in mpg I changed tire size and tire type. I assumed the change in mpg was due to the tire size going from 33-35” and my gearing being less than adequate. Good question.

P.s. I believe the Cooper STT Pro is a hybrid tire, and not a full MT. I know I loved my set. I’ll be going back to Cooper next time.
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Cooper and MT make good stuff. Just hope Goodyear doesn't screw it up now that they own them. I heard Dick Cepek is gone now, or going away.

Changing size can make a big impact, gear reduction, aerodynamics can hurt you a lot. Adding width has a huge impact on rolling resistance.
 
I have the Cooper Evolutions and feel like they really perform well offroad and don't hum too load on road. Seem to be pretty good tires and reasonably priced.
 
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JHammett said:
I have the Cooper Evolutions and feel like they really perform well offroad and don't hum too load on road. Seem to be pretty good tires and reasonably priced.
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Same, I like them and they've done great both on and offroad
Brianj5600 said:
There are 2 M/T offerings from Cooper. The Evolution M/T is between an All Terrain and an honest M/T. The Discovery STT Pro is a real M/T.
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Not sure I'd classify the Evolution as a hybrid MT. If the Evolution is an in-between tire, the Baja Boss is too.

MT Baja Boss:
1682526920353.png

Cooper Evolution M/T
1682526944969.png
 
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Brianj5600 said:
Which tires are those? Can you post the other Cooper to the above post?
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Sorry, I added labels to the images. I tried to get it to display them side-by-side without success. The MT Baja Boss is first, the Cooper Evolution MT is below. Is there another version of the Evolution?
 
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