I keep hearing that bigger tires will result in worse fuel milage. I am thinking of going just a little larger than the stock tires and wheels. At what point do you guys start seeing your mileage change? I am currently getting 18+ stock and really don't want to loose much. Any examples are greatly appreciated.

 

When I put the BFG 315s on I lost about 1-1.5mpg city driving. My highway mileage stayed right about the same.

 

My 315s cost me about 1-1.5 MPG in combined highway/city. Probably about 60-70% highway. Then I went to 285s and got about half of that difference back. Plus the truck drives better with 285s.

Wetspirit

 

Yep same here traded in the tiny stockers and filled the wheel wells with a set of BFG 315's I went from 20 and change down to low 19s.

 

Changed from 245 to 265 and had a little more aggressive tread. Dropped 1.7 city 1.5. HWY. Had running numbers for 12Years.

 

First off, I need to state that I have a 6 speed, and you have an auto. The auto guys seem to lose a little and the 6 speed guys seem to gain. With that said, I gained about 2 mpg switching from stock 265s to 315s. I currently get 21 mpg w/ my 35s on. This is not a 'best tank' number, but a true MPG as I keep track of all the fuel that goes into my truck. See my prior post "MPG Graph for last 53,000 Miles!" for the graph - the graph shows when the 315s went on.
https://www.dieseltruckresource.com/d...d.php?t=129749

 

Remember guys, when you put bigger tires on you throw your speedos off.

 

My results are the same as Mark's. With the g56 and 315 BFGs on stock rims, I gained a little on mileage. (I used the flashpaq to correct for larger tires.) The majority of posters running autos lose mileage with the bigger tires.

 

True.
Is everybody correcting the math for thier results?

 

It's not so much the height of the tire but the width.
A tall skinny tire will do better than a short wide tire. as long as you keep the engine in it's sweet rpm range.
Also an agressive tread tire will do worse than a smooth street tire.

So a tall skinny tire with smooth tread design and somewhere close to 2000 rpm will do best!
Michelin LTX are very good at this!

 

I can't speak for everybody, but my speedo is corrected.

 

I agree, but the only other option to run a 35" tire is to go to a 265/70-19.5. Then you would also have the benefit of being able to run at higher pressure. I would love to do that, but don't see spending $2K to $3K to put on some Rickson's.

 

Good point mark also I do not want to replace my fillings those 19.5s cant ride that good

 

With my G56, in 6th, w/3.73's it is almost like a NVG5600 and 4.10's. 2.91:1(G56/3.73's) vs a 2.99:1 for the 5600/4.10's. I want to go to a taller tire big-time.