Just saw your signature running stock tires, answered my own question LOL
So here's my guess off the top of my head
- The height of the truck + the tires will have more of an effect at highway speeds IMHO, bigger profile cutting through the wind.
The Rebel is on a knife edge anyway, in terms of MDS being on (fuel savings up) and MDS being off (fuel savings down).
Changing the aerodynamic resistance + adding engine load to get and stay moving will take it down a bit.
I'm going to guess your highway MPG might end up being a little over 18mpg
- Around town, I'm going to pull a number out of thin air and say 14.1mpg
The toyos aren't terribly heavy, rolling resistance seems good compared to the duratracs, and you went with 34.3s and not 35x12.5s
(That size, while common - when compared to the stock size, is heavy, wide, and tall.)
If you're looking to get back MPG, an it was something I thought about?
I added a mopar ram air intake and a magnaflow exhaust. In my personal opinion it lets the engine just breath and function better. The engine just didn't seem to work as hard audibly, visibly in its rpm range on the same roads.
MDS was able to kick on sooner and stay on longer. Air in, exhaust out. I personally believe I added just about 1mpg highway, around .5mpg around town, .7 average - between the 2.
I personally believe the power is delivered faster and more efficiently. Oh, and the highway power at speed, when the air is flying at the front of the truck, slams into the intake, down a very short path that's properly sized right into the engine - that power at speed is better.
