Seems on the high side but possible. They’re pretty heavy. I know on our Tahoe they def hurt it about 3 mph averageTank of fuel on the trip to Indy netted 16.1...
Could the Duratracs cause a loss of 2-3mpg?
I went from 19.2 mpg empty doing 75 on interstate from FL. with Cooper 245/75’s down to this low of 9.0 with 265/75 Duratracs towing 7k on the interstate @ 75.
Odometer mileage shows consistently 2% less than actual measured mileage over 50 miles on the highway markers.
Speedometer reads about 2mph slower than actual, measured by time/distance and gps.
Need to recalibrate the speedo with the upsize in tire. Check it with a Gps app on your phone for a idea on how far its out.
As posted above Dean, the 2% less actual road mileage difference is negligible compared to the 15+% drop in fuel mileage.


Clear takes longer to dry, you need to make more lighter passes more spaced out.