For those of you with 315's what kind of mileage are you getting? what truck?

I am driving a 2005 Chevrolet CC LB 4wd, 3:73, 6" RCD with 315-17's and I am getting about 11-12mpg with 900 miles on the truck so far. Appreciate any input.

15-19MPG WITH 80,000. I have found my Foot:o and different fuels effect mpg drastically

but i see 1mpg difference between my 285 and 315

Around town about 15-17. On the freeway, cruise set a 75, flat ground, about 20-23. I'm happy with it.

i just changed from 305-70-16 to 315-75-16, and have noticed a bit of a drop off. Getting about 13-14 around town in stop and go ( by far the worst driving conditions for mileage ), about 15-17 when its not stop and go, and 18-20 on highway. as mentioned above, alot has to do with driving conditions and that pesky right foot

14 to 15, according to the DIC, but my speedo is off about 5 mph so im sure that should be figured in also. I started using a soy type fuel conditioner and it gained me about 1 mpg.

I went from 3:73 to 4:11 and gained 6mpg getting around 19-21mpg):h

I have 35's with about same mileage as you (850) and am getting between 11-12 mpg also. I hope it gets better with more miles. My speedo is corrected and I figure with calc.

I went from 3:73 to 4:11 and gained 6mpg getting around 19-21mpg):h
are you being serious on this ? did it get that much better changing the gears ?

I question the accuracy of that statement also. Turning 35's it would be very diffacult to achieve that kind of MPGs with any gear set up.

I dont know and I don't care. I didn't buy my truck for fuel economy reasons, I would have bought a 4 banger for that. I would guesstimate that I get in the 15s with my setup.

I also didn't buy my truck for mileage, but for the towing power, and to get into the offroad places I put the lift to avoid clearance issues. But it is nice to brag about good MPG, with such a big truck. I am hopefull that the 15 MPG will come once I get more miles on the truck. Keep the input coming! ! !

Yes, the gear ratio does make that much of a difference, due the fact that with the stock 3:73 gear and the 35's will put your power band out of range. With the 4:11 gear, the power band is near its original margin. :eek: I have not corrected the speedometer yet to get an exact mpg, but I do know that it increased the mpg by 6mpg and it is around 19mpg:D

On edit: this is for an LB7, sorry forgot where I was.

16-17 in town, 19+ on the freeway. Predator is on the 85 tune.

Pro-Comp 33's are the same as 315's

I am avgeraging 15-17 around town........usually 19-20 on a trip.

Depends how much idling I do.

T:D NY

Actually, 305/70R16 is equivalant toa 33/12.50R16. And 315/75R16 is equivalant to a 35/12.50R16):h

Yes, the gear ratio does make that much of a difference, due the fact that with the stock 3:73 gear and the 35's will put your power band out of range. With the 4:11 gear, the power band is near its original margin. :eek: I have not corrected the speedometer yet to get an exact mpg, but I do know that it increased the mpg by 6mpg and it is around 19mpg:D

With everything else being the same there is no way you are going to see a 50% increase in mileage with just a gear change.
If your driving style changed from leadfoot to lightfoot then MAYBE you would see that much difference. I'm not trying to start a war here but there has got to be other factors if you really did see a 6mpg increase.
Blake

any more with mileage input?

I will add mine. 04LLY. Before my lift and tires I saw between 18-19 mpg freeway and 15-16 city. Now with my rancho lift and 285 tires I am seeing anywhere from 12.5-14 mpg. My lift and tires have been on for about three weeks. I am not sure if it is the lift and tires causing the drop or also the winter blended diesel. I think both of these factors are contributing.

Eric