Bird
Rest in Peace
I agree that if fuel economy were the reason, it would make sense to recommend the synthetics, but who knows. I got my information (whether right or wrong) from a Quaker State representative. I had been using 10W-40 and when I saw the recommendation for the 10W-30 in the owner's manual, I got curious. Since they make and sell both, the guy would have no reason to give out erroneous information (unless of course he simply didn't know and made up a story).
Bird
Bird