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

There nice.Super smooth and heavy duty.Used them for an anchor system on a drift boat that I’m building

Its not actually a deep V. Its more comparable to a u groove.

Much better than the plastic rollers that came with zip line originally. Built to last!

Good high quality bearings. Works great in my pully system I have set up in my garage.

These are the best I can find. I wish they were cheaper but quality sometimes costs.

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 arent 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 doesnt matter (no joke intended), but not sure why you would put dimensions in a listing if they arent right.

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.

Used these on the mast of a sailboat. Perfect fit. It helped that the dimensions were clearly shown in a photo. Bearings rotate smoothly.

Not 7mm as described. When another reviewer said it fits a 1/4 inch bolt well, that is because it IS a 1/4 hole.

Good size but are u groove not v groove like advertised