uxcell R188ZZ Deep Groove Ball Bearings Z2 1/4 Inch x 1/2 Inch x 3/16 Inch Double Shielded Chrome Steel Skateboard Bearings Sealed Industrial Bearings10pcs

nice little bearings. I needed to replace some metric with 1/4" x 1/2" o.d. and these fit nicely. I did have to shim the outside of the bearing using some .0002" brass shim stock but that was only because the the bearings were metric before and I needed to use an axle that had 1/4-20 threads on it. I have some spares too.

I purchased these to upgrade my Zebco 33’s. If you get them, make sure to lube them before installing. I was under the impression they were preluded and ready for use. Wrong, I had to tear one reel completely down again and hand lube each and every bearing. They worked fine after casting numerous times. They also fit perfectly which was a pleasant surprise. If you want preluded bearings go with high dollar bearings from an industrial supply store and be ready to pay much more. No more than what I plan to be using them, these will work just fine.

AKA: The “You Didn’t Know You Needed These Until You Did” BearingsThese R188ZZs are the sleeper MVPs of anything that spins. I grabbed them for a 3D printed mini turbine project, and they’ve since found their way into a fidget spinner rebuild, a sliding drawer mod, and even a DIY rotary encoder test rig. They're shielded, compact, and smooth as silk when installed properly.Z2 tolerance means you’re getting solid mid-grade precision—not quite aerospace, but plenty good for most hobby and light industrial builds. Pop these into a printed housing or bearing block, and they’ll quietly spin forever while you admire how much smoother everything feels.

There does not appear to be grease on the bearings. If there is it must be a very light coat. I plan on putting some ngli 1 super lube grease in them as it's thinner and shouldn't slow down my usage(fishing reel bearings). I would disassemble and grease before long term usage. The shield clips come off easily and then use a sewing needle to pop out the shields. Looks to be a plastic cage so be sure and use a grease compatible with plastic.

Have only used them in light duty applications but they have been fine. Hard to believe the price..

I've used these to fix a globe and make a few fidget spinners. They spin great and seem to last.

I bought these to replace the damaged bearing in my fidget spinner. They are okay. Just okay. They rotate smooth and are decently quiet, but they maintain no momentum. The moment you stop applying force, they'll stop rotating. The bearings I had before could rotate for well over five minutes with a single strong flick. This go two seconds at most, and I wish that was an exaggeration.I don't know if it's because they have a lot of grease/lubricant in them or what, but generally I'm disappointed with them. If you just need something that turns smoothly when pressure is applied, these will do great. They fit as expected and would be well priced for that purpose. But if you need it to keep spinning, then these ain't it.

I got these to make like wind spinners. I have yet to make one, but these seem well-made and smooth. I would definitely buy them again.