I've been running Yoko G015's in 35/12.50/20 since last fall for the snowflake rating. I really prefer the 295/70/18 size and weight rating. The weight savings of dropping down will be roughly 10-12 lbs per tire/wheel vs my existing setup, depending on the tire. Does anyone think I will notice any real difference in performance or mpg if I make the swap?

 

Maybe a little, but not a whole lot. I just went kind of the other direction, from 275/65r20 (34.1x10.8) to 295/65r20 (35.1x11.6) and didn't see enough of a difference to really make it be worth it to switch back to the smaller size.

The 295/65r20 size is one you might consider...it's a hair taller than 35/12.50x20 but if I remember right, it was actually a bit lighter (because it's not as wide).

Going to the 295/70r18 size will affect how it fills up the wheel wells a bit, as well as the stance from front/back.

 

I think you will notice it drives better, more than you will any performance gains, especially with your 4.30's. My truck drives great, but I feel the wider 12.50 tire, when then asphalts not great, wanting to track more than the old 285's I had.

 

Well, I shall see. I went ahead and ordered the 295's in Michelin Defenders. I will report back any noticeable difference.

 

After 3 tanks now, I can say I'm up at least 1 mpg with the new Michelin's. I also towed 10k yesterday, and the truck definitely towed better and had more power. I got 9.3 mpg on the hour round trip with my machine which was better too.

 

Nice! That is the tire size I'm going to once I wear out the goodyears...if I can wait that long.