Stainless Steel 5mm Deep U Groove Ball Bearings Pack of 2, Pulley Bearing Wheel Rail Ball Bearings Wheel

Perfect fit for Slackers Night Riderz zipline trolley. Upgrade or replacement.High quality bearings and machining on them was top notch.

Replaced Zipline wheels, these fits perfectly and have lasted thus far

Bought to fix our Zipline in the yard they are perfect

They seem to work as the originals that came with the zipline kit, they do wear out fast lol but satisfied that the kids could play again

Nice product. Machined and surface finished nicely. Rolls smoothly around the axis. No crunchies as they say. I actually bought more for my project they were so nice. Hopefully this is a good supply going forwards.

The bearing I just received (S608z) seems to be of nice quality (maybe a 4 or a 5). Seems tight and good finish. But the dimensions listed aren't close to actual. The bearings I just received had an outside diameter of 31.5mm, and a width on outside of shoulders of 12mm (10.43mm for width of rotating pulley). The shaft appears to be closer to .25" (6.4mm). And depth of groove is 2.8mm. Maybe size doesn't matter (no joke intended), but not sure why you would put dimensions in a listing if they aren't right.

These fit perfectly and immediately made the zip line faster.

Our zip line OEM bearings were so cheap that they were worn out after less than three months of very light use. These units made our line faster and smoother than new. Haven’t had them long enough to report on longevity.