The tread on the rear tires might not make full contact at first, but with proper tire rotation, it should not be an issue (it will NOT shorten the treadlife of the tires, although trying to compensate by running lower air pressure WILL).
When I had 32x11.50R15s on mine, I ran them at 35 PSI front, 30 rear, and rotated them every 5-7K miles. Had about 25K miles on them when they reached half-worn (50% tread left).