Gmc 2500hd Gas Mileage (6.0)?

[tbone7213]

I just bought an 04 GMC 2500HD with a 6.0. I took on a 400+ mile hunting trip and checked the mileage and it was 11.3 mpg and I wasn't pulling anything. I have 285/75/16's on it so I know it is not accurate so how do figure the actual miles traveled? I am guessing it to be about a 5-7% difference. Thanks in advance.

[masterp2]

I just bought an 04 GMC 2500HD with a 6.0. I took on a 400+ mile hunting trip and checked the mileage and it was 11.3 mpg and I wasn't pulling anything. I have 285/75/16's on it so I know it is not accurate so how do figure the actual miles traveled? I am guessing it to be about a 5-7% difference. Thanks in advance.

 

multiply the number you came with by the ratio of tire diameters

[tbone7213]

Are you saying multiply the odometer miles traveled by the tire ratio?

[ws6_guy]

next time on a trip re-set the avg economy ( hold button in while in Ave Econ mode u ntil it resets to zero )

[Ranger]

next time on a trip re-set the avg economy ( hold button in while in Ave Econ mode u ntil it resets to zero )

 

He may not have that option if there are no steering wheel controls. My 06 2500HD didn't have it.

[ws6_guy]

next time on a trip re-set the avg economy ( hold button in while in Ave Econ mode u ntil it resets to zero )

 

He may not have that option if there are no steering wheel controls. My 06 2500HD didn't have it.

 

 

oh ok, dont know if he has the drivers information center or not.

[masterp2]

Are you saying multiply the odometer miles traveled by the tire ratio?

 

just take the mpg you calculated, and multiply it by the tire diameter ratio.

 

Tirerack.com has complete diameter information

[HDdave]

I wen't through this when I got my 285's. Multiply the miles on your tank by .072 and then add that number back on to the miles and divide it by gallons. As far as I know, that produces an accurate number...

[Tipsovr]

I wen't through this when I got my 285's. Multiply the miles on your tank by .072 and then add that number back on to the miles and divide it by gallons. As far as I know, that produces an accurate number...

 

 

That is one of the best tips I have gotten off this board. Thanks! That is exactly what I needed to figure the mileage on mine. Still sucks, but at least I know for sure how bad.... Still love the truck though!

[masterp2]

[cvandegna]

I wen't through this when I got my 285's. Multiply the miles on your tank by .072 and then add that number back on to the miles and divide it by gallons. As far as I know, that produces an accurate number...

 

 

That is one of the best tips I have gotten off this board. Thanks! That is exactly what I needed to figure the mileage on mine. Still sucks, but at least I know for sure how bad.... Still love the truck though!

 

 

 

The correct formula is (new tire diameter/stock tire diameter) x measurement

 

Measurement can be your speed from speedo, gas mileage from DIC, and odometer/trip mileage. All your readings will be under/over-stated by that factor because your rolling length is different per rev (but you knew that already).

 

You can either do it in metric mm (keep in mind that you have to find the tire diameter from this: Width x Aspect Ratio = Section Height; Section Height x 2 = Combined Section Height; Combined Section Height + Wheel Diameter = Tire Diameter)

 

Easier to go here: Tire Conversion

 

Oh yeah - I get 12 mpg in mixed driving, 9 mpg when towing my 32' RV (+/- 7000#). I am running Hypertech 93 octane programming, 4.10 gears and have 35" tires though.

[Prairiefire]

I saw a 6-7 m/gal increase with a muffler change & cats removed,

[masterp2]

I saw a 6-7 m/gal increase with a muffler change & cats removed,

 

it's amazing what can happen with a 50 kt tailwind.

 

Where do these people come from?

[jlucas]

04 2500HD 2WD 4.10 automatic, all stock - snug top shell

Columbus to Effingham (340miles) - empty, cuirse set at 70mph - 15.8mpg

Effingham to Columbus - 20ft enclosed trailer (8.5 ft wide) 6000lbs, cruise at 70mph - 9.8 and 9.6mpg

[22zxla]

my 02 i brought from brother with 86000 miles last yr. has 4:10 rear auto. Anyway first week drove all interstate and would go 400 miles with qtr tank left. Figured at the time was 15/16 mpg. fast forward to this summer, truck now has 95000 miles and was going to tow the boat to destin . Had tune up eject cleaned etc, and put 265 tires on . Well took off and only went 300 miles a empty tank. Boat is about 3500lbs and tires are revos. I was shocked at the bad milage. Well now im driving mostly city with 20 % hwy and now im still stuck on 300 miles per tank. so long story short im at 10mpg ,guess its the tires?