6.7L mileage with oversize tires??

[CHKelley]

2007-2008 6.7L 4X4 owners: I'm getting 17+ mpg around town, almost 20 on the highway. I've been told this will increase somewhat as the cummins breaks in, maybe up to 22 on the highway.

I'm going to mount either 295, 305, or 315's on my 2008, wondering how everyone's mileage is with any of these oversize tires.

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2008 QCSB 6.7L 4X4 2500 6-speed Mineral Gray

[CW6.7]

Is that hand calculated?????? Most people bone stock are seeing 12-13. With MP-8 or some form of chip some are seeing 15, 16, 17. Again with the DPF delete gaining even more mpg's. Tires size will kill that in a hurry!!!

I have run about 3000k miles on my DPF delete kit and MP-8. I have been averaging 18 mpg. With 305/45-22's (about 33x12.5)

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07.5 - QC - SB - 6.7L - 68RFE - Afe intake - TS MP8 - 5in Magnaflow TBE - Gear Alloy 22x9.5's with 305/45's - Bilstien 5100s - Ultralite 2 gauges.

[6.7L OneTon]

Those can't be hand calc'ed numbers unless you somehow drive downhill wherever you go. :-) I lost about 1-1.5 mpg off my hand calc'ed numbers when I went from the stock tires to 315/70 17s. The loss is about the same with the true 35" Toyos I'm running now.

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2007.5 3500 SRW 6.7L, 68RFE, PW flares, UConnect, Infinity, EZ Gate,
KORE 2.5 Stemtop Chase system with control arms, 35" Toyo M/Ts

[Garry Verheyden]

I'd do anything to have that kind of mileage!! My 08 Mega Long has never seen over 13MPG. Mostly it would get 11 MPG. empty!! I took my 19.5's off and now am in the upper 12's. My steel 19.5's were 33-1/2" tall with the 245 tires. They ate 1-1/2 mpg average.

[DUKFVR]

Not a 6.7 ,but a 5.9 & I lost about 1 1/2-2 mpg when I went to 35's Toyo's.

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2007 2500 5.9 CTD MegaCab 4X4 Patriot Blue, Carli Starter System, Thuren TrackBar, Carli L/T AirBags, 35/12.50/17 Toyo M/T's on Black H2 Wheels, Denver Offroad Front Bumper, Buckstop Rear Bumper, Wet Okole Seat Covers, WeatherTech Floor Mats, WeatherGuard Tool Box

[DunesRunner08]

You don't even want to know how sheety my fuel economy is with the 40's on it...lol

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2007 Dodge 2500 & 2006 Ford F250

[CHKelley]

The numbers I'm reporting (17/20) are the ones calculated by the overhead console electronics in my 2008. My truck is bone stock running 265/70/17's and I don't have a lead foot. Yet.

Maybe I should start hand calculating my mileage??

Anyhow, thanks for the replies so far. I'm sure I should expect 1-2 mpg loss if I increase a tire size or so.

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2008 QCSB 6.7L 4X4 2500 6-speed Mineral Gray

[kmwharley]

Just curious to the guys that lost mpg with larger tires, did you correct for tire size? On my wifes truck she never remembers and when I tell her that because of the larger tire size she if off 10% I see a light :-). If you are not correcting for the tire size on the speedo then maybe you are not actually losing any, maybe a little? Just a question

[DUKFVR]

Originally Posted by kmwharley

Just curious to the guys that lost mpg with larger tires, did you correct for tire size? On my wifes truck she never remembers and when I tell her that because of the larger tire size she if off 10% I see a light :-). If you are not correcting for the tire size on the speedo then maybe you are not actually losing any, maybe a little? Just a question

I hand calculte mine with the different size tire figured in. I lost about 2 mpg with the toyo M/T's. Running 315 BFG A/T's for summer & I lose about 1-1 1/2 mpg.

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2007 2500 5.9 CTD MegaCab 4X4 Patriot Blue, Carli Starter System, Thuren TrackBar, Carli L/T AirBags, 35/12.50/17 Toyo M/T's on Black H2 Wheels, Denver Offroad Front Bumper, Buckstop Rear Bumper, Wet Okole Seat Covers, WeatherTech Floor Mats, WeatherGuard Tool Box

[ricefarmer05]

Hand calculated i get about 19 on the highway and 14 around town