Fuel mileage with 245s

rob103180 · **Posted:** Tue May 23, 2006 6:14 pm

I have an '06 CRD and just recently put 245/75s on it. What kind of fuel mileage have you guys been getting with the same scenario? Thanks!

pipefactory · **Posted:** Tue May 23, 2006 7:10 pm

rob103180 wrote:

I have an '06 CRD and just recently put 245/75s on it. What kind of fuel mileage have you guys been getting with the same scenario? Thanks!

I got 25.5 with 245/75 Revos

LibertyCRD · **Posted:** Wed May 24, 2006 8:47 am

I averaged 24 mpg. 255/70-16s took me down to about 21 mpg average.

ATXKJ · **Posted:** Wed May 24, 2006 3:55 pm

I put lift, ARB and 245/75/16 MTRs all at the same time - dropped about 3 1/2 mpg - I was so surprised - I put the stock wheels & tires on for a week to see how much they affected it and - virtually no difference 19.93 vs 20.5 - that's within my tank to tank variation (no EVIC) - I think the lift and ARB caused enough aerodynamic change (under body airflow drag) to do most of the mileage loss. (I'm debating a air dam to test the theory).

Also - the MTR's are 72 lbs per wheel/tire - stocker's are 46 lbs - so if you accelerate or decelerate - you have a lot of extra momentum that must be created, removed - so if you're doing stop and go driving they'll have more effect than if you have an uninterrupted drive (I'm about 80% highway to/from work)

MudTrac · **Posted:** Wed May 24, 2006 4:09 pm

I really wish I knew what was the deal with my milage. I only get like 15MPG with my 245's and before that wasnt much better than 17...? Im in FL and winter blend I dont think is an issue here? Ive tried all sorts of diesel from chevron / BP / Sunoco, nothing changes, and Ive been on long road trips avg like 65-70MPH and still only get like 16 at best. If I drive it hard nothing different. What do you think it is? I have like 9K miles on it so far. Ive never gone past the 350 mile mark on one tank and this is all hand calc not evic

Goglio704 · **Posted:** Wed May 24, 2006 4:27 pm

MudTrac,

It might be worthwhile to take off the intercooler hose at the EGR flow control valve and make sure it is opening all the way. I've not had it happen, but have heard it claimed that if this valve sticks closed mileage will really suffer. Seems like it would set a trouble code for air flow, but it would be worth looking at anyway.

MudTrac · **Posted:** Wed May 24, 2006 7:05 pm

ok guess ill try and look at it, i was going to get a provent, a friend has one for me. I dont think this is the issue but i can allways check, the jeep is only 3.5 months old and only has 9K miles

LibertyCRD · **Posted:** Thu May 25, 2006 7:34 am

You definitely have a major problem with your CRD. With a lift kit, 255s, and 6,870 lbs. load on my CRD going up steep hills and on the Interstate some, I got 14 mpg with mine. So if you are getting 15 mpg empty...you have a major problem I would think.

MudTrac · **Posted:** Thu May 25, 2006 8:23 am

well im going by 22 gallons in my tank when filled and then i only get 340 miles on one tank so that would be 15.4 and even if you take out the 2 "spare" gallons for the reserve then its still like 17.... not so good. But I drive on a yellow light till i can find diesel.

BCool · **Posted:** Thu May 25, 2006 12:15 pm

Hmm, I've never gotten more that 18.5-19 in my tank, you might be over caculating the tank size a bit, that will help your mileage with 18 gallons you'd average about 19.

mOlson · **Posted:** Thu May 25, 2006 12:42 pm

City: 20
Highway: 20
Mixed driving: 20
Wheeling and mixed driving: 20
Loaded up with luggage and people: 20

No EVIC, just miles/gallons.

Wonder what I would get in mixed driving going backwards...

FWIW motor has ~7K on it.

MudTrac · **Posted:** Thu May 25, 2006 3:28 pm

BCool wrote:

Hmm, I've never gotten more that 18.5-19 in my tank, you might be over caculating the tank size a bit, that will help your mileage with 18 gallons you'd average about 19.

just checked the last fill up ticket and it has down 20.45 gallons, i mean i really wait to fill it up just to try and sqeeze some milage out of it. And try and make my tank wait till i get paid again.

rob103180 · **Posted:** Fri May 26, 2006 4:26 pm

The 2006s have a 20.5 gallon tank. I have been getting 380 miles with 245/75s. I fill up when the gas light comes on.

MudTrac · **Posted:** Fri May 26, 2006 5:02 pm

I thought it was 22.5? thought there was a 2gallon reserve...
I looked at my old gas tickets and they are all like 20.something gallons... and I know there had to be a little gas left also... thats weird

well if it was 18 gallons that would be more like 19mpg not so bad i guess but still want better than that.

blacksmoke · **Posted:** Fri May 26, 2006 8:50 pm

mOlson wrote:

City: 20
Highway: 20
Mixed driving: 20
Wheeling and mixed driving: 20
Loaded up with luggage and people: 20

No EVIC, just miles/gallons.

Wonder what I would get in mixed driving going backwards...

FWIW motor has ~7K on it.

You would get -20 going backwards :lol:

Fossil Fool · **Posted:** Fri May 26, 2006 11:57 pm

MuddTrac
I thought i was the only one with the lousy mileage. I just got tired of whining about it cause I was the only one! Who knew, misery loves company.
I average 15.6 around town mostly stop and go, driving like an old lady. I have the daystar lift and will be putting on moabs w/245 MTRs soon. So I can expect even worse afterwards.
But I was getting around the same from day one. Maybe its just Florida (I'm in Deerfield Beach). Probably the Bermuda Triangle!
I had the EGR fixed awile back but it didnt change. I am hoping the tsb for the transmission will help!

rob103180 · **Posted:** Sat May 27, 2006 4:59 pm

I am not sure about a reserve. I looked at the window sticker and it said 20.5 gallon tank.

blacksmoke · **Posted:** Sat May 27, 2006 6:57 pm

rob103180 wrote:

I am not sure about a reserve. I looked at the window sticker and it said 20.5 gallon tank.

Yup, same here for my '05. Maybe "reserve" is the word to use when the low-fuel warning lights up? Then I'd said a bit under 2 gallons are left, but I wouln't like to risk running out :shock:

too expensive for a diesel (air in the lines, pressurize, etc.)

Fuel mileage with 245s

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