I've been using an older Powertap SL 2.4 hub over the past few years, and am having issues with the bearings that I'm guessing is due to premature wear.

The original bearings lasted around 8,000 - 10,000 km before I replaced them due to excessive play. I replaced them with a set of HSC hybrid ceramic bearings. They ran great for a while, then developed excessive play by around 5,000 - 6,000 km, then suffered bearing failure whereby one of the seals popped open and some of the ceramic bearing fell out during a ride! Obviously I was not impressed!

My newest bearings are a set of hybrid ceramic VXB. Again, they worked fine and were smooth as silk for the first 3,000 km or so, but now they too have excessive play. I'm concerned that they too will fail soon.

My question is why these bearings are not lasting any longer. Is it a problem with the design of the hub, and is this what I can expect in the future? Is it a problem with the quality of the bearings I've been using? Would I get better life out of a name brand steel bearing like SFK or FAG?

FWIW, I've installed the replacement bearings myself using a home-made bearing press. I use a thread rod with washers that are large enough to apply pressure only on the outer bearing race and not the inner one.

I'd appreciate any thoughts you might have on this matter!

Thanks in advance!

Try steel bearings. Bicycle-market ceramics often have loose seals that let dirt and water in.