Singles on mine, and the front end wear seems not to be an issue with this rig.
If you don't pay attention you will scrub the rears off first. I will try to get pictures of it this weekend when I am in the parade (NM State fair parade, we sponsor Keep New Mexico Beautiful and the state litter control mascot 'Dusty Roadrunner').
By the way, I saw a funny bumper sticker on a Dodge with a lift and stacks the other day it stated "My engine weighs more than your car".

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07.5 3500 Quad, SRW, 4X4, Laramie, Leathered, Dark Metallic Gray, 6.7, 68RFE, 20K Reese, Ride Rite's, 2 Viair air compressors, Bully steps, Kleinn Locomotive air horns (5 in all), Billet polished locking fuel door, 'A' pillar mount Auto Meter Pryo, PML X-deep trans pan
06 Durango 285 RL 5'er Lifted by KZ