Premature wheel bearing failures.

I know those tend to go bad around here with all the dummies running oversize tires (pointless on a truck IMO), my Jeep has unit hub bearings on the front axle too; buddy of mine with a similar XJ Cherokee said he was going through hubs every 6 months after putting on big tires (either 33" or 35" I can't remember) until he finally swapped in a Wagoneer Dana 44 front axle with locking hubs and whatnot.

Get Timken or SKF, I replaced the hubs on my Jeep with one of those two brands about 6 years ago and they're still cherry even with plenty of off-roading trips. I only have 29" tires though which helps a lot.