Yeah, those wheels (or spacers) caused the problem. I don't think it was a lug nut issue since it appears that the brake rotor was still attached. So most likely what happened was that the wheels with the very wrong offset overstressed the bearings and the axle failed. There are a few guys around town who have those stupid looking wheels on their trucks. The wheels stick out 4 or 5 inches from the correct location which puts a huge amount of stress on the wheel bearings. Tire shops should know better than this but some of it could be self installed by guys buying rims on-line and just bolting them on at home.
All the axle does on that truck is pass through the bearing. Essentially it's a flanged bearing with the hub on it, the axle passes through it. Looking at the brake rotor it doesn't appear there is a ton of offset in the wheel. My guess is that it was wheel bearing failure, who knows what caused it, but I doubt it was the guy who installed the wheels.
A friend of mine lost the front wheel on his Ram truck a few years ago because of bearing failure. He had just got off the interstate and had stopped at the intersection of the highway and off ramp. When he took off the wheel, hub and brake assembly cam off. It could've been bad if it had came off just a few minutes before when he was going 80 mph on the interstate. He said he never felt anything strange in the steering wheel.
