I purchased a set of these for the rear carrier on my 04 LTZ400. I don't have any complaints with how they went in and the bearings and seals looked of decent quality. However, around 10 months after installation, I find myself with the ATV apart, punching out a set of bad bearings. Upon punching them out, one of the inner seals of the bearing came off. The whole thing was rusty with no trace of grease, which I found odd but maybe it washed out.
Now, where I live and ride, there are quite a few creeks that I must cross on trails, so if you ride in a dry area, this review may not be worrisome. The axel on my quad isn't dipped or pitted where the seal sits, so I don't see why these bearings failed so early. Like I said, I am sure the water and grit of creek water done my last pair in but that is the reason there are seals. I did not purchase a second set of these and most likely won't, seeing as how All Balls are cheaper, and I probably will do bike surgery to fit some grease zerks on the carrier if the next set fails.