Low MPG with 33s R18 load E tires

Lioska

Well-Known Member
First Name
Alioscha
Joined
Aug 21, 2020
Messages
45
Reaction score
90
Location
Redmond, Washington
Vehicle(s)
tacoma
Vehicle Showcase
1
Hi, wondering if anyone else is in the same situation. I got Nittos grappler tires 275/70/18 load E on stock Sahara wheels and I am getting about 15 mpg (mostly city) with no lift or mods.

I noticed the tires are about 58 lbs each and I have seen 285/70/17 load C at around 38 pounds (20 lbs difference).

Is it right to assume the additional weight on the tires are the main reason for the low MPG or that's expected for mostly city driving ?





Advertisement

 
Last edited:

Maverick909

Well-Known Member
First Name
Brian
Joined
Jan 15, 2019
Messages
1,582
Reaction score
1,620
Location
SoCal
Vehicle(s)
2018 JLU Sporticon, 1976 GMC K15 Lifted on 35's
Looks like you have a sport in your profile pic. Have you recalibrated the ecu? If not your Jeep is going to loose mpg quite a bit as the engine module needs correct information to shift the transmission correctly for the tire and gear sizing. I’m am currently running 4.10s and 33” tires and avg 20mpg on my last overlanding trip of 1500 miles. Including over 500 miles of dirt travel
 

aldo98229

Well-Known Member
First Name
Aldo
Joined
Nov 16, 2019
Messages
4,435
Reaction score
9,122
Location
Bellingham, WA
Vehicle(s)
2018 Jeep Wrangler Unlimited Sahara, 2018 Fiat 124 Spider Abarth
Occupation
Market Research
Vehicle Showcase
2
I had 275/70R18 KO2s on my Sahara: didn’t see an impact on MPG.

Now that I got a lift and 35-inch tires, I do.
 

mwilk012

Well-Known Member
Joined
Mar 10, 2018
Messages
3,801
Reaction score
3,227
Location
Oklahoma
Vehicle(s)
2018 Ocean Blue JLU Rubicon
The calibration isn’t the problem, your heavy foot and admittedly mostly city driving is the problem.
 

Black Jeep Convertible

Banned
Banned
Joined
Sep 1, 2020
Messages
1,184
Reaction score
1,177
Location
NYC
Website
www.amazon.com
Vehicle(s)
'19 JLU Sport S 2.0T eTorque
Occupation
Amazon Influencer 😂
Hi, wondering if anyone else is in the same situation. I got Nittos grappler tires 275/70/18 load E on stock Sahara wheels and I am getting about 15 mpg (mostly city) with no lift or mods.

I noticed the tires are about 58 lbs each and I have seen 285/70/17 load C at around 38 pounds (20 lbs difference).

Is it right to assume the additional weight on the tires are the main reason for the low MPG or that's expected for mostly city driving ?
Did you reprogram your new tire size? If not, do that first with tazer https://amzn.to/3wIlHZ7
 
OP
OP
Lioska

Lioska

Well-Known Member
First Name
Alioscha
Joined
Aug 21, 2020
Messages
45
Reaction score
90
Location
Redmond, Washington
Vehicle(s)
tacoma
Vehicle Showcase
1
Thanks for the replies, I have a sport altitude that came with 32s tires so would the difference from 32s to 33s be big enough to impact the transmission shift and MPG? Do people that move from 32s to 33s usually use the tazer?

I don't drive aggressively but will try to watch it more closely to see if that makes a difference.
 
OP
OP
Lioska

Lioska

Well-Known Member
First Name
Alioscha
Joined
Aug 21, 2020
Messages
45
Reaction score
90
Location
Redmond, Washington
Vehicle(s)
tacoma
Vehicle Showcase
1
I had 275/70R18 KO2s on my Sahara: didn’t see an impact on MPG.

Now that I got a lift and 35-inch tires, I do.
Did you use the tazer when you installed the 275/70R18?
 

liquids

Well-Known Member
First Name
Bill
Joined
Dec 18, 2017
Messages
340
Reaction score
267
Location
Detroit
Vehicle(s)
2018 JLU Sport S, 1968 CJ5
Lots of rotational inertia in heavy tires. The starts and stops of city driving require lots of energy to spin them up and lose lot of energy in heat loss off the brakes. Highway driving probably wouldn't have as much of a hit to your mileage.
 

BlackGenesis

Well-Known Member
First Name
Andrey
Joined
Dec 4, 2019
Messages
486
Reaction score
445
Location
Muskegon Michigan.
Vehicle(s)
18 Sahara unlimited
Recalibrating does not make difference in MPG. It now takes more gas input to accelerate at the samerate as beforehand, hence your city mpg Is worse. Higher wheel weight at greater distance from center of rotation is your enemy.

I believe Firestone destination X/T is the lightest tire you will find in the side of 275/70.
 

grimmjeeper

Well-Known Member
Joined
May 6, 2021
Messages
161
Reaction score
296
Location
Castle Rock, CO
Website
www.grimmjeeper.com
Vehicle(s)
1987 Comanche, 2001 Cherokee, 1997 F250
If you don't recalibrate you will log fewer miles so it absolutely will affect the mileage on your dash. City vs highway driving will affect your mileage. Aggressive acceleration will lower your mileage. Driving really fast on the highway (over 75) will really hit your mileage.

And the dash gauge is never accurate to begin with.

If you want true mileage, get a GPS to get true distance and calculate your mileage manually.
 

aldo98229

Well-Known Member
First Name
Aldo
Joined
Nov 16, 2019
Messages
4,435
Reaction score
9,122
Location
Bellingham, WA
Vehicle(s)
2018 Jeep Wrangler Unlimited Sahara, 2018 Fiat 124 Spider Abarth
Occupation
Market Research
Vehicle Showcase
2
Did you use the tazer when you installed the 275/70R18?
Didn’t have to. The speedometer came off by 1.5 MPH from the factory; it was right on the mark with the 33-inch tires.
 

Black Jeep Convertible

Banned
Banned
Joined
Sep 1, 2020
Messages
1,184
Reaction score
1,177
Location
NYC
Website
www.amazon.com
Vehicle(s)
'19 JLU Sport S 2.0T eTorque
Occupation
Amazon Influencer 😂
Didn’t have to. The speedometer came off by 1.5 MPH from the factory; it was right on the mark with the 33-inch tires.
If you want a more accurate reading you’re going to have to
 

aldo98229

Well-Known Member
First Name
Aldo
Joined
Nov 16, 2019
Messages
4,435
Reaction score
9,122
Location
Bellingham, WA
Vehicle(s)
2018 Jeep Wrangler Unlimited Sahara, 2018 Fiat 124 Spider Abarth
Occupation
Market Research
Vehicle Showcase
2
If you want a more accurate reading you’re going to have to
Apparently I didn’t say it well.

So here is another try:
  • Jeep came with 32s; speedometer was off by 1.5 MPH —I checked my speed multiple times against radar.
  • Replaced OE tires with 33s; speedometer reading became spot-on without a Tazer
Now I got 35s: the tires measure 34.5 inches mounted, but had to set the Tazer at 33.75 to get an accurate speedo reading.

It appears the Jeep’s tire size calibration settings are off by about 0.75 inches.
 

Advertisement




D&C Designs
 



Advertisement
Top