Is 23mpg a pipe dream?

[Da Capt]

Brand new 2024 Willys 4 door 3.6 auto soft top here. Theoretically, my vehicle is rated at 23mpg highway. I only have 400 miles on it so I realize it's a brand new engine and mileage should increase a little once it's good and broken in, but I'm guessing this thing will never see 23mpg on the highway. Not with these heavy 33" tires and a 4.10 rear end. Maybe a 2 door sport with street tires, but not this Willys. Are there any 2024 Willys 4 door, 3.6, autos getting 23mpg on the highway? My work commute is all highway, 23 miles each way. I tried to hypermile it the other day. Didn't go over 60mph. Averaged 18.7mpg.

Only one way to find out lol. The opinions will be split on this one. But I’ve got as high as 23-25 mpg with stock duelers on long trips. When I went to all terrains 32 inch went down to 18-20 mpg

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[TheRaven]

Really? Were you able to get that right off the rip or was it after a certain number of miles on the odo?

No, it does take time to "break in" before you will see your best mpgs. Though it's impossible for me to say when. I think by about 3k I was seeing 22-23mpg on the highway. But that just may be when I first noticed it.

The first time I took it down to the beach house (it probably had about 10k on it) I saw mileage I never thought was possible with the 3.6 - driving between beach towns on a dead flat, straight, 55mph road for 30 mins I saw 29.2mpg. That helped me to understand how some members on this board are able to brag of hitting 28-30mpg while others can barely hit 20mpg...it's easy when you aren't constantly going up or down.

Lightweight tires are the key to this. I cannot stress enough how much tire weight matters. The stock ATs are super light...when you go to bigger tires you really need to avoid the D and E-range options...they murder fuel mileage.

 

[autotragic]

No, it does take time to "break in" before you will see your best mpgs. Though it's impossible for me to say when. I think by about 3k I was seeing 22-23mpg on the highway. But that just may be when I first noticed it.

The first time I took it down to the beach house (it probably had about 10k on it) I saw mileage I never thought was possible with the 3.6 - driving between beach towns on a dead flat, straight, 55mph road for 30 mins I saw 29.2mpg. That helped me to understand how some members on this board are able to brag of hitting 28-30mpg while others can barely hit 20mpg...it's easy when you aren't constantly going up or down.

Lightweight tires are the key to this. I cannot stress enough how much tire weight matters. The stock ATs are super light...when you go to bigger tires you really need to avoid the D and E-range options...they murder fuel mileage.

I get the same fuel economy with D range 35s as I did on stock 33s.

I definitely got better fuel economy down in Florida than I do up North that's for sure the flat terrain does help. Unfortunately that's just not realistic everywhere can't be that flat.

 

[TheRaven]

I get the same fuel economy with D range 35s as I did on stock 33s.

I definitely got better fuel economy down in Florida than I do up North that's for sure the flat terrain does help. Unfortunately that's just not realistic everywhere can't be that flat.

There are some light D-range tires (as there are also some really heavy C-range tires)...it's not a hard and fast rule, just a common correlation. GENERALLY, D-range tires are heavier than C-range.

 

[autotragic]

There are some light D-range tires (as there are also some really heavy C-range tires)...it's not a hard and fast rule, just a common correlation. GENERALLY, D-range tires are heavier than C-range.

My tire/wheel combo is almost 100 lbs.

Edit for clarification it's 96 lb without wheel weights or air.

 

[TheRaven]

My tire/wheel combo is almost 100 lbs.

Nope. Absolutely no way you didn't lose fuel mileage going from stock tires to 100lbs per corner. Not happening. There are other variables at play in your case.

 

[autotragic]

Nope. Absolutely no way you didn't lose fuel mileage going from stock tires to 100lbs per corner. Not happening. There are other variables at play in your case.

You're right I gained effective gear ratio which lowered my RPMs going down the road.

 

[jadmt]

mine can easily get the rated mpg. I have gotten better at times.

 

[TheRaven]

You're right I gained effective gear ratio which lowered my RPMs going down the road.

Oh yours is MT. So there's the other variable.

 

[Remorseless]

Nope. Absolutely no way you didn't lose fuel mileage going from stock tires to 100lbs per corner. Not happening. There are other variables at play in your case.

Stock JT 285/70s on Method wheels is 93lb per corner, and the Methods are only a couple pounds heavier than OE. Some of the OE spec'd wheel/tire combos are heavier than you'd expect.

 

[autotragic]

mine can easily get the rated mpg. I have gotten better at times.

My Rubicon is rated 17 city/25 highway which is laughable at best. There is a thread around here somewhere that talks about Jeep lowering MPG ratings for the 2024 refresh.

 

[TheRaven]

Stock JT 285/70s on Method wheels is 93lb per corner, and the Methods are only a couple pounds heavier than OE. Some of the OE spec'd wheel/tire combos are heavier than you'd expect.

Well yeah, obviously that matters...but for instance - I initially went from stock 32's to 33's (aftermarket wheels), and gained I think like 7lbs per corner. I instantly lost 0.5mpg. I then went from those 33's to super-lightweight 35's, so my 35 wheel/tire combo was within 1lb of my former 33 wheel/tire combo, and I lost zero mpg.

The overriding point here is that you need to minimize your tire weight gain when you upsize your tires to avoid losing (too much) fuel efficiency. The stock offerings, whether we're talking about the Sport/Sahara on-road ATs or the Rubicon off-road ATs, are all going to be among the lightest in their respective classes. So that makes it trickier to upgrade.

 

[Twojayhawks]

You can enjoy smiles per gallon or miles per gallon but not both. They are mutually exclusive.

 

[Remorseless]

Well yeah, obviously that matters...but for instance - I initially went from stock 32's to 33's (aftermarket wheels), and gained I think like 7lbs per corner. I instantly lost 0.5mpg. I then went from those 33's to super-lightweight 35's, so my 35 wheel/tire combo was within 1lb of my former 33 wheel/tire combo, and I lost zero mpg.

The overriding point here is that you need to minimize your tire weight gain when you upsize your tires to avoid losing (too much) fuel efficiency. The stock offerings, whether we're talking about the Sport/Sahara on-road ATs or the Rubicon off-road ATs, are all going to be among the lightest in their respective classes. So that makes it trickier to upgrade.

Somewhat true for the KO2s - they sit around 50lb, but they're a special variant for Jeep (they also have a 285/70/17 for Ford). The common aftermarket KO2s in 285/70/17 (LR E) are ~60lb though, middle of the pack.

For the AT3Ws on the JT, they're about 60lb, which is middle of the pack.

 

[jadmt]

You can enjoy smiles per gallon or miles per gallon but not both. They are mutually exclusive.

I dunno know new corvette gives you both

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