13.2 mpg with 37s....

[runningshoes]

OP - what were you getting before the changes?

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[WranglerMan]

I’m running BFG AT KO2’s, 315/70/17 on a stock JLUR, had the dealer reprogram for 35’s and am getting 15mpg around town. I would expect 37’s to deteriorate mileage from there if that helps. Getting about 20mpg straight highway driving.

I’m running the same setup and my mileage is about the same as you, stock gears and I seldom see 8th gear

 

[McGilli]

Had to do the math.

You're getting 17.9l/100km

Ouch! Hurts my wallet seeing that

 

[Elsinore73]

I’m running the same setup and my mileage is about the same as you, stock gears and I seldom see 8th gear

I have a manual and can only usefully hold 6th gear above about 70mph, provided there is not much of an incline.

 

[Ehmsea]

37s BFG all terrain, no regear - I drop to 14 mpg in the cold winter, pick up a few mpgs (16 - 18) in the summer...
Ohio, no hills...

 

[track.n.trail]

I'm on 37" KM3s and beadlocks. 3.6 V6, 8 speed, armor and stock 4.10 gear. I get 14-15 around town and 17-19 on the highway.

You're running a SUPER heavy and very high rolling resistance tire. That along with your right foot will heavily affect your MPG.

 

[WranglerMan]

I have a manual and can only usefully hold 6th gear above about 70mph, provided there is not much of an incline.

I had the gear I was in displayed but recently turned it off as I got kinda crazy watching it jump between 7 and 8th gear, I do remember my stock days not long ago when it got 22-23 on the highway but as I added things like lift, tires, steel bumper, winch those miles ticked away.

 

[BHo]

I’m on 4.10:1 gears with BFG 37x12.50R17 at 32psi. I verified my tire size by doing a circumferential rollout C/π = d, programmed my flash calibration tool to the true diameter, verified speedometer with GPS.
I don’t push hard on the throttle and do interstate between 65-75 mph. Currently, I’m getting 18-20mpg on Highway and 16-17mpg city. I’ve been monitoring for the past 6 months.

 

[jeeeep]

2021 JLUR, hard top. Plastic bumpers. 35” spare.

tires -37x13.50r20 Nitto Mud Grapplers.

Mostly city driving, commute to work.

I expected a decrease from the 37s, but 13.2 is pretty bad.

ive considered an intake and exhaust, maybe a tuner and gears in the future.
Thoughts??

35" spare?

what tire pressure are you running? as others have stated, the mud tread is pretty aggressive and will affect mpg more than like a BFG KO2.

I switch out between my 37 Cooper STT and 37 BFG KO2, always worse mileage with Coopers

 

[kapk22]

35" spare?

what tire pressure are you running? as others have stated, the mud tread is pretty aggressive and will affect mpg more than like a BFG KO2.

I switch out between my 37 Cooper STT and 37 BFG KO2, always worse mileage with Coopers

38-40 psi. I haven’t dropped it down to 30-32 yet. I can’t imagine the coopers would be any worse than the mud grapplers.

still have decent power though. And I don’t drive it hard at all.

 

[40”JLURD]

This thread makes me glad I got a diesel. Guys are getting 24mpg on stock gears with 37’s all day long on those motors.

Looks like the ole “you’ll never make that motor cost up in fuel savings” wives tale may not hold up so well with 37’s or larger. At 10mpg +/- that’s a huge delta between the two motors.

At 13.2 mpg it would take 3,787.87 gallons of gas to drive 50,000 miles.

At 24 mpg it would only take 2,083.33 gallons of diesel to go the same 50k

Average Oregon Gas Price is $2.59
Average Oregon Diesel Price is $3.27

$2.59 x 3,787.87 = $9,810.58 Gas Cost

$3.27 x 2,083.33 = $6,812.49 Diesel Cost

Fuel Savings in 50k miles = $2,998.09

So depending on how long you want to keep your Jeep you may want to consider trading in for the diesel motor if MPG with 37’s is a concern.

 

[kapk22]

This thread makes me glad I got a diesel. Guys are getting 24mpg on stock gears with 37’s all day long on those motors.

Looks like the ole “you’ll never make that motor cost up in fuel savings” wives tale may not hold up so well with 37’s or larger. At 10mpg +/- that’s a huge delta between the two motors.

At 13.2 mpg it would take 3,787.87 gallons of gas to drive 50,000 miles.

At 24 mpg it would only take 2,083.33 gallons of diesel to go the same 50k

Average Oregon Gas Price is $2.59
Average Oregon Diesel Price is $3.27

$2.59 x 3,787.87 = $9,810.58 Gas Cost

$3.27 x 2,083.33 = $6,812.49 Diesel Cost

Fuel Savings in 50k miles = $2,998.09

So depending on how long you want to keep your Jeep you may want to consider trading in for the diesel motor if MPG with 37’s is a concern.

probably take me five years to drive 50k miles, especially if I drive the yj off and on during the summer. Good point though. I will keep an eye on the mileage and also do a manual check this next week and see how it compares. Thank you guys for all the input.

 

[Yellowssm]

Ive got a 2020 JLUR w/2.0T etorque, tuned with JB4 (around 20 more whp, 30-40 more wtrq), hard top, steel bumpers, skid plates, 2.5" MC lift, 37" patagonias on OEM wheels, borla exhaust, with the stock 4.10's and I get 17-19mpg combined city and highway when Im driving it normal. When im driving it hard I get 15 +/- mpgs.

 

[jdubya421]

As others have said, I have 37s, 3" lift, the works, but geared to 4.88 on MT and I am getting about 16mpg (with the V6).

 

[limeade]

This thread makes me glad I got a diesel. Guys are getting 24mpg on stock gears with 37’s all day long on those motors.

Looks like the ole “you’ll never make that motor cost up in fuel savings” wives tale may not hold up so well with 37’s or larger. At 10mpg +/- that’s a huge delta between the two motors.

At 13.2 mpg it would take 3,787.87 gallons of gas to drive 50,000 miles.

At 24 mpg it would only take 2,083.33 gallons of diesel to go the same 50k

Average Oregon Gas Price is $2.59
Average Oregon Diesel Price is $3.27

$2.59 x 3,787.87 = $9,810.58 Gas Cost

$3.27 x 2,083.33 = $6,812.49 Diesel Cost

Fuel Savings in 50k miles = $2,998.09

So depending on how long you want to keep your Jeep you may want to consider trading in for the diesel motor if MPG with 37’s is a concern.

What you're not accounting for in your equation is the initial cost of the Diesel engine over the base engine. I just built two identical JLUR's on the Jeep site, selecting no options for one with base engine and only the diesel option (which included some mandatory options) for the other. The diesel equipped JLUR cost $49,885 and gas equipped was $43,885. That's a $6,000 difference for a diesel Wrangler. A third optional build is with the 2.0T engine and automatic transmission at $45385. That's still $4,600 cheaper than the diesel.

Based upon your math (which I did not check as I assume it's correct), I can drive the base gas engine 100k miles before I would break even on the cost of the diesel equipped Wrangler. Or I can drive roughly 75k miles on the 2.0T with auto before reaching the cost of the diesel option.

This doesn't take into account the higher maintenance costs of the Diesel engine either......more frequent fuel filter changes, oil changes cost more due to larger oil capacity, DEF, etc.

I'm not degrading the Diesel engine. For those who don't necessarily need a diesel, it can be hard to justify the higher initial cost when it takes a long time (and at least 100k miles) to recoup the initial premium cost vs. a gasoline engine.

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