I don't think thats actually the case. I believe that was a misperception..... I think that actual cause of higher gas mileage with truck nuts is due to the folks behind you speeding up, to check and see if you REALLY DID hang those things off your hitch..... causing a pressure wave to help push your truck along.

Works best on crowded freeways.

 

Well this was a waste of time.

 

Bigger size then before? Switched from a street to an all terrain or mud tire? That would be why.

 

good point on the tread design... a member here stated a while back he lost 3mpg just by going to an aggressive tread design...

 

This is true i lost a couple when i switch to hankook dynapros atm

 

I gained approx 2mpg when I switched from my BFG All Terrains to my Moto Master street tires. Same tire size and everything just different tread pattern. Less resistance i guess.