Increase tire size and better MPG?

[Ken1]

I have a 2006 dually that came with 245/75R/17E OEM tires and wheels. I would like to increase tire size, what would my max size be 265, 285, 305’s?
I have 4:10 gears any idea of tire diameter and change in gear ratio?
Looking for some improvements in fuel MPG opportunities?

 

[Sawboy]

Bigger tires = More rolling resistance and more weight.

That all adds up to WORSE mpg. Leave em be. Best mpg saver is your right foot.......

 

[the_hammer]

I can second that. I just put on a set of Toyo Open Country M/T

My mileage has dropped from 6.4 km/L to 5.8 km/L.

 

[bushpilot]

unsprung weight is your WORST hp/mpg enemy

 

[Ken1]

Thanks for the replies and Lets en this topic.

Thanks

 

[kenholl]

You also lose torque when you go to bigger rubber. Reduced torque requires more fuel to move the same amount of weight (truck, trailer, etc)

 

[banyon]

Ken1, I agree with everybody on the tire size. I`ve always put a bigger tire (for looks) on my trucks but with the price of fuel I`m going closer to stock. My last dually had 265`s & it didn`t hurt the mpg very much. If you`re not going bigger for looks then leave it stock.

 

[ckamp52]

i stuck with the stock size 265's when mine wore out but just got a more aggresive tire. mileage is the same but the grip is better. i also have had many compliments on them and how much just changing to the more aggressive style made my truck look better and i have to agree

 

[lvtitan]

well i don't know from all the metric sizes but i do know that w/my 3.73 gears i lost quite a bit of mileage with my 35" tires. i have PLENTY of HP to move the truck, that's not a problem, but 4.10's would bring me back to the stock ratio. i'm doing gears next week, but unsure if i'll just do the 4.10's to bring it back where it was and keep the speedo right, but i'm leaning towards the 4.30's because i have a large turbo and need the higher rpms to help spool it.