Diesel and Big Tires

[GARRIGA]

Obviously doing something that drops fuel economy by a certain percentage, use 10% for easy math, will cause a larger drop in mpg in the vehicle with the higher numbers. Using that 10% the vehicle with 20 mpg drops to 18, the vehicle with 30 drops to 27; the vehicle with 30 mpg loses 3 while the one with 20 loses 2.

My contention being that percentage less for diesel vs gas with unsprung weight of bigger shoes comparable to loading more sprung weight observed when towing with a diesel vs gas with the former have the lesser hit to mpg.

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[jeepncrowd]

For some prospective. I have a 2015 Eco diesel WK2 Overland 4x4. Stock I got about 20 city & 27 HWY (30.5" highway tire). With the GDE tune it bumped it up to 21 city 29 highway. After all mods it dropped to 19 city 23 highway. That's about what the 5.7 HEMI gets stock.
The 32" tires, the ARB bumper and Roof rack by far are what gave me the hit on the highway (the bumper being the biggest culprit)

 

[GARRIGA]

For some prospective. I have a 2015 Eco diesel WK2 Overland 4x4. Stock I got about 20 city & 27 HWY (30.5" highway tire). With the GDE tune it bumped it up to 20 city 29 highway. After all my addon it dropped to 19 city 23 highway. That's about what the 5.7 HEMI gets stock.
The 32" tires, the ARB bumper and Roof rack by far are what gave me the hit on the highway (the bumper being the biggest culprit)

Seeing how city took a minor hit and most of the loss was on highway then could it be the roof rack causing the major loss where aerodynamics play heavily on efficiency? Surprised tune only returned 2 plus on highway and zero benefit city. Still better than Hemi stock. That's good enough for me.

 

[jeepncrowd]

For some prospective. I have a 2015 Eco diesel WK2 Overland 4x4. Stock I got about 20 city & 27 HWY (30.5" highway tire). With the GDE tune it bumped it up to 21 city 29 highway. After all mods it dropped to 19 city 23 highway. That's about what the 5.7 HEMI gets stock. The nice thing is that it had almost no effect on the city mpg.
The 32" tires, the ARB bumper and Roof rack by far are what gave me the hit on the highway (the bumper being the biggest culprit)

 

[jeepncrowd]

Seeing how city took a minor hit and most of the loss was on highway then could it be the roof rack causing the major loss where aerodynamics play heavily on efficiency? Surprised tune only returned 2 plus on highway and zero benefit city. Still better than Hemi stock. That's good enough for me.

IT was the ARB bumper that really did it. The tires dropped it by 2-3 mpg, the bumper dropped it by 3. and the rack maybe 1. ITs hard to say. THat was the order I put them on

 

[GARRIGA]

IT was the ARB bumper that really did it. The tires dropped it by 2-3 mpg, the bumper dropped it by 3. and the rack maybe 1. ITs hard to say. THat was the order I put them on

There goes my idea. Lol

 

[Smoke Hound]

Does anyone have some real world data on this. I’m mean other than speculation it seems everyone here is lacking personal experience with the Wrangler EcoDiesel. I have had mine for 16 months and 24xxx miles. The best MPG I have gotten is 28 on a 600 mile highway road trip. But normally I get about 22.4 and that about 60/40 split city/highway respectively. I have a Willys edition with factory Firestone MT tires. I’ve been considering changing to a 35 but the few people I have seen who have don it are all Canadians and when you convert their numbers from liters to gallon I calculate about 17mpg.

I’m just curious, with the unprecedented high cost of fuel right now, would it be foolish to put 35s or even 33s on. We off road about 12 weekends a year and the stock tires have served us ok. But I’d like to get a better foot print. So if you have some real life experience with this I’d love to hear about it.

 

[Terpsmandan]

I am running 37" KO2's and was getting around 21 mpg. She gets the same on hers running 35" RG's. I put in a GDE tune and it upeed my mpg to 22-24 depending on whether it's windy or not with a high of 28 mpg up in the Adirondacks (45-55 mph and no stop lights).

 

[BroncoHound]

Does anyone have some real world data on this. I’m mean other than speculation it seems everyone here is lacking personal experience with the Wrangler EcoDiesel. I have had mine for 16 months and 24xxx miles. The best MPG I have gotten is 28 on a 600 mile highway road trip. But normally I get about 22.4 and that about 60/40 split city/highway respectively. I have a Willys edition with factory Firestone MT tires. I’ve been considering changing to a 35 but the few people I have seen who have don it are all Canadians and when you convert their numbers from liters to gallon I calculate about 17mpg.

I’m just curious, with the unprecedented high cost of fuel right now, would it be foolish to put 35s or even 33s on. We off road about 12 weekends a year and the stock tires have served us ok. But I’d like to get a better foot print. So if you have some real life experience with this I’d love to hear about it.

This thread is 4 years old and the Gen3 EcoDiesel hasn’t yet been released in the Wrangler. Of course it’s all speculation. There has been ample real world experience outlined in these forums in the years since. Look at half the threads in the first page of the EcoDiesel section and they nearly all talk about fuel economy with larger tires.

I’ve been running true 35” tires (load range E Duratracs) since my EcoDiesel Jeep was brand new and, now at 6300 miles and with a roof rack, roof tent, and cargo box mounted 100% of the time, I’ll average 21.5-22mpg on the freeway if I keep my cruise control set at 75mph. On a recent 1000-mile blitz run home to Montana, I had the cruise set at 85mph the whole way and averaged 18.4mpg for the trip.

Before I installed the tent and cargo box (but still had 35” tires and roof rack), my economy was about 1-1.5mpg better in all scenarios. The fuel economy also improved as the engine loosened up (typical with diesels) and seems to still be getting a bit better though that could also be due to warming temperatures and conversion back to summer blend #2 at the pumps.

 

[Terpsmandan]

Pushing a lot of air is not so good for our barn door aerodynamics....

 

[grimmjeeper]

This thread is 4 years old and the Gen3 EcoDiesel hasn’t yet been released in the Wrangler. Of course it’s all speculation. There has been ample real world experience outlined in these forums in the years since. Look at half the threads in the first page of the EcoDiesel section and they nearly all talk about fuel economy with larger tires.

I’ve been running true 35” tires (load range E Duratracs) since my EcoDiesel Jeep was brand new and, now at 6300 miles and with a roof rack, roof tent, and cargo box mounted 100% of the time, I’ll average 21.5-22mpg on the freeway if I keep my cruise control set at 75mph. On a recent 1000-mile blitz run home to Montana, I had the cruise set at 85mph the whole way and averaged 18.4mpg for the trip.

Before I installed the tent and cargo box (but still had 35” tires and roof rack), my economy was about 1-1.5mpg better in all scenarios. The fuel economy also improved as the engine loosened up (typical with diesels) and seems to still be getting a bit better though that could also be due to warming temperatures and conversion back to summer blend #2 at the pumps.

I'm running the same Duratracs without any rack, tent, or cargo box. I average mid 20s on summer blend fuel at freeway speeds. 24-25 or so.

On back roads where I'm running 60-65 MPH I have pushed almost 30.

Though I did put in a 2.5" lift and mileage has come down a little. No solid numbers yet this summer since the lift.

 

[zouch]

there are tons of threads here about MPG on EcoDiesels with larger tires already.

in summary, mine went from about 28MPG when stock to low-mid 20s running a 3" lift and 35" MTs.

Does anyone have some real world data on this. I’m mean other than speculation it seems everyone here is lacking personal experience with the Wrangler EcoDiesel. I have had mine for 16 months and 24xxx miles. The best MPG I have gotten is 28 on a 600 mile highway road trip. But normally I get about 22.4 and that about 60/40 split city/highway respectively. I have a Willys edition with factory Firestone MT tires. I’ve been considering changing to a 35 but the few people I have seen who have don it are all Canadians and when you convert their numbers from liters to gallon I calculate about 17mpg.

I’m just curious, with the unprecedented high cost of fuel right now, would it be foolish to put 35s or even 33s on. We off road about 12 weekends a year and the stock tires have served us ok. But I’d like to get a better foot print. So if you have some real life experience with this I’d love to hear about it.

 

[Wrangler man]

there are tons of threads here about MPG on EcoDiesels with larger tires already.

in summary, mine went from about 28MPG when stock to low-mid 20s running a 3" lift and 35" MTs.

That said and so true not one other Jeep Wrangler platform can say the same.

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