I too have been a little dissapointed in the lly's mileage. driving home from the dealer it averaged 18.4, which I was impressed with, but it has never been that high since. Pulling a little two place snowmobile trailer, i was only seeing about 11 mpg. I put 305's on it right when i got it home. could this have affected it that much? It didn't seem to drop the LB7 that far.