My MDS kicks in very randomly, just under 4kmi on my truck so far, seems to be kicking in less and less now. Maybe the fairly sudden dropping change in temp in my area has an effect on the air/fuel ratio and the way its being consumed needs the mds less or more now? Over the summer seemed to kick in a lot and in the past two weeks upstate NY has gone from 65 degrees to 35-50 degrees. I noticed my mpg was much higher two weeks ago. probably 2mpg's or more. I have 3.92's with 20" wheels and stock tires.
Your biggest issue is the 3.92 gears with the 17" wheels which is making you run higher rpm than a ram with 20" wheels with the same gears and same speed, so you're not in the sweet spot for mds as much
I doubt that matters? I have 3.92's with 20" wheels, but the tire size should keep the gear ratio the same, the wheel size doesnt affect the gear ratio if the tire sizes differ making the tallness of tires the same between a truck with 17" wheels and another with 20" It ultimately boils down to gear ratio and overall wheel/tire size not just wheel.
Easy example a 35x12.5x20 may be the same as a 315x65x17...its in the sidewall of the tire not necesarily the wheel size.
Now plus side for your post against mine, is i have no idea if the stock tire sizes make up for or go along with the wheel size on the new rams. Meaning if the dodges with 17" wheels come with a (just for example) 265x60x17 and the 20" wheels come with a 285x75x20 then the 20" wheeled truck will have a taller tire making the gear ratio less even if both vehicles have 3.92's.
As most of you I'm sure already know, first number is width, second is sidewall and third is wheel size in metric measurement; and in standard like the 35x12.5x20, the first is overall height second is width and third is wheel diameter.
Mine kicks in all the time I do have it disabled below 50 as I hate it in town and in traffic on the freeway.
How do you disable/program mds, need a tuner/programmer or can this be done from vehicle controls?