Fuel Mileage Honesty

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Grand Mesa

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My son runs 285 75R18 (18 inch wheels) tires on his 2014 Ram 2500 Cummins diesel 4x4 which is a 35" tire and the same width as my 2016 Power Wagon's factory stock 33" tires. It's a good choice for going taller as it is with the 285 75R17 at 34". He said that the taller tires did not impact his mpg with his manual transmission and 3.42 gear ratio. It is still around 14 mpg (hand calculated based on GPS) with his nearly 5 ton in weight truck.

Going taller and not wider lowers the highway RPM especially in the 75, 80, and 85 mph (Texas) speed zones which should save some fuel with our 4.10 and 4.56 gear ratio Power Wagons. It's a heavier tire than the stock size and so that should have the opposite impact on the fuel mileage.

The 285 75R18 tire is somewhat fair in choice and availability. The plus is that it should have no rubbing issues with a stock Power Wagon due to it isn't any wider than the stock 285 70R17 size. Also, living in the snow country going any wider than a 285 width tire on unplowed mountain roads isn't my first choice. Tall and narrow tires is always the safest thing at least for me for winter driving.

My plans are to go with the 285 75R17 tires though in order to not cut my mpg from 17 plus on the Interstate and to not have to purchase some 18 inch wheels in order to run the 285 75R18 size. If some manufacturer made a 285 80R17 (35") sized tire that would be my choice.
 

mt goat

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North bend Washington
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Dealer said they installed 35’s on my truck when I bought my truck new and after doing some research there more like 34’s and I have a 23 mile drive to work through several small towns and two lane highways and am getting 13.7 miles on 92 octane
 

Grand Mesa

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Been traveling for the past two weeks visiting and spending time with family while towing my 17.5 foot travel trailer. Over 3,000 miles so far. Best gas mileage is at 70 mph at 10.4 mpg, at 75 mph it drops to 9.1 mpg, and at 80 mph it drops like a rock. Gas consumption was a concern with my Power Wagon due to the lack of any services in most of the areas I travel. So I seldom exceeded 70 mph and carried extra gas. My son took this photo with his Ram 2500 diesel while heading towards the Sheldon National Wildlife Refuge where we camped remotely.image000000.jpg
 

Brakelate

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We get the same scenarios down my way. This one taken in Northern/Central Nevada.
Luckily, the TT carries fuel in it's own little station, as due to some unanticipated head winds sucked more fuel than I had calculated and ended up coasting to a halt just a mile or so outside of Minersville. Soooo embarrassing.


KIMG0395.jpg
 
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