Unpossible. <img src="/forums/images/graemlins/lol.gif" alt="" /> There's no way simply unlocking your hubs could make mileage *worse*. The most "friction" they could have would be if they were locked, like the drive flanges.

I do agree that mileage savings are generally pretty insignificant though, and the real benefit is reduced wear and tear on the CV boots.

'97 4Runner, '06 F350, '86 4Runner, '05 WR450
http://home.4x4wire.com/erik