[George16]

Your test makes sense. If you think about it, the badlands with bigger lugs provides better traction compared to the bowties (or any smaller lugged tires for that matter) on the surface you're running. Since the bowties are slipping too much (therefore slower speed for the truck), you would have to press the trigger harder (compared to running with the badlands) to try and compensate thereby increasing the amount of energy used.

The heavier badlands seem to be more desirable on this type of surface since it provides better traction than the bowties.