Z-First High Speed 608RS Hybrid Black Ceramic Bearings for Longboard, Inline Skates, Skateboard, Scooters, Skateboard and More (Pack of 4, Black)

These are excellent bearings, spin is exceptional.

Bought these to replace a set of steel bearings in dishwasher circulator pump. The originals were made in Japan, 608z. The motor was only 18 months old and cost $125; decided to try a bearing replacement this time.Machine tolerances are pretty good.ID bore was probably a hair (maybe a couple thousandth of a mm at most) lager than the 608z steel orininals. Can tell this because a bearing puller was required to remove the original 608z, and these were able to slip over the motor shaft with a few taps from a small hammer.Runout was better than expected from a bearing targeted to the skateboarding market, maybe .5mm at most consudering its nearly impossible to find true specidications the moment a product can also be used for non critical applications like fidget spimners. (The original steel bearings were also, I estimate, about the same .5mm)Free spin time was excellent until, of course, the covers were popped and a dab of bearing grease was applied. All bearings require grease except perpaps full ceramic but even those might want grease in this kind of application. Grease caps of these were a disk of what appears to be stainless, pretty hard stuff, coated with red rubber on the outside. Balls inside are white idicating Zr base. Cage is translucent brown of unknown composition but seems OK for now. Will see if the red bearing grease I applied begins eating the cage over time.Research indicates I can expect at least 3x the life out of these over steel in the little dishwasher, and considering the Japanese 608z steel only lasted 18 months that equated to, at best, 120 hours of continuous runtime, seems pretty weak to me for an expernsive part that's so important to this household.Will install this in the dishwasher and follow up in about 6 months if this listing still exists. So far, I am very impressed considering the target market is basically fidget spinners and I can't find a single video of a person press fitting a ceramic bearing to fix any kind of motor, but it went very smoothly.So far: Thanks for making a good bearing with decent toleranced.

INSTALLED IN HEELY SHOESThese are great I'm super happy with them but like all ceramics you need to maintain them very often clean them with non-chloronated brake cleaner (usually green can) then use oil to lube them

Great quality for the low price. Used to rebuild motor bearing in milwaukee angle grinder. They worked perfectly and made rebuilding the motor easy. The motor spins smoother than before.

these are garbage, they make crunchy noises when installed into my Heelys , the bearing says ABEC 11 rolls worse and sounds worse than the ABEC 5 bearings that came with the HeelysDO NOT BUY!!!

The bearings are well made and spin freely. The bearing covers are easy to open and lubricate. But the sleeves are not stainless steel. Note the picture.

Excelente calidad, muy buen material, contento con la compra

I would have thought these ceramics would have lasted a little longer than a few miles. I should have asked for a refund.