Quoted from DCP:
I have 3 or 4 broken ones just like that from Harbor Freight! They can't support the weight of a pinball machine (for very long...). The HF ones are rated at 132 pounds, which is really borderline if you hit a bump or anything. The caster just falls apart, and you have to lift up that end of the machine to kick the remains of it out. <=== Personal experience! LOL
They tend to disintegrate at the most inopportune times, leaving you with the machine wobbling on the other very overloaded casters. I have seen much heavier-duty looking versions of these, but they are $10-12 each. Probably worth it to buy the better ones!
I had some of the Harbor Freight ones as well....they are quite a bit different. I have had a couple of sets of these for some time now, and I drag them all over my shop and haven't had an issue. I never looked at the weight rating, but I am sure it is more than 130 pounds.
Edit: Website says rated for 200lbs ea. But moot at this point, I believe the sale is over.