[special-K]

I beg to differ on that, sorry. After running these in many trucks over the years I have never found either to be true. Mileage is not affected by a locker. They present no more rolling resistance that an open rear. I've owned two '72 3/4t pickups that got identical mileage. Both had everything the same except the GMC had a Power-Loc and the Chevy had a No-Spin and they both got 12.5 mpg.

On rear tires wearing, you just need to know how to drive a locker. You drift it around the sharp turns, unless you like to hear the tell tale chirp and wear on your tires. I've driven trucks with lockers so much, that is how I always make my turns. At a light making a left, for instance, I give gas to get going, cut left, roll around the bend, then hit the throttle. It's a good way to drive anything to prevent fishtailing on greasy rainy streets, even with open rear. Tires on an open rear will wear less driving this way as well.