On my Wildcat I noticed outside edge of the rear axle right side tire wore. The tire was also closer to the other. Also that equalizer was pushed forward. What I found was the leaf spring on the wore tire axle, was overstressed and when the spring looses it's arch, it gets longer. In turn the stretched spring, pushed the axle forward, since it's bolted solid in the rear, causing the tire wear.
Clear as mud?
Also I believe what caused this was the previous owner had used a ramp under the tire to change a tire. All the weight on the spring flattened it out.
*Current: 2005 Ford F350 Crew Cab Dually 6.0 diesel 4x4*
*Retired: 1987 F350 Crew Cab Dually 6.9 turbo diesel
2007 Forest River WildCat 32QBBS