Genetic Karyotype JIS Sealed Bearing Square Taper Bottom Bracket - 68 mm

I recommend this product

Excellent well made bb…lightweight and good fit

I recommend this product

Excellent engineering and light 254g. I managed to fit this into a very rusted frame where I had needed to cut out and remove the old and broken BB. This replacement is so smooth. I can't recommend it highly enough and as usual SJS delivered it easily and quickly.

I recommend this product

Mounted easily, though some written guidance would have been helpful. Bearings smooth, crankset mounted easily and tightly.

Firstly, I'm not sure why this BB is described as for "that ultimate fixie machine", I can't see anything about the BB that makes it suited to fixed gear riding (what would that even mean?)

Haven't fitted mine yet. Seems reasonably well made. The machining on the flats of the taper is very rough. I'm not sure if this will cause a problem in practice but I've never seen such rough machining on a BB before. Axle spins smoothly under hand pressure. The design is a fairly standard sort of cartridge BB type design where you can pull off the left side cup to see the sealed bearings. It doesn't look like it would be terribly difficult to replace the bearings.

The axle is hollow which is nice. At first I imagined this would b a rebadged Token BB but holding the two side by side it is clear they are a different design.

I suppose time will tell how this BB holds up.