Hub bearing weight

[rom]

I have some 15mm ID 24mm OD bearings from a Zipp hub which weigh 7.6 grams each. These bearings do not seem very durable. Do any other manufacturers use this size? Would it be worth the weight penalty to build hubs with 2 bearings per side? Does anyone know of a hub built with 2 bearings per side?

What kind of life have others experienced from this size of bearing?

Is there a better bearing size which is a sealed cartridge style?

Sorry for all the questions but I have not seen any high end hubs, other than a Zipp.

[Knuster]

I think you can get better bearings from SKF or any other Producer. They manufacture bearings in nearly all sizes and qualities.

[BikeTech]

rom, I do know that American Classic rear hubs have four bearings, two per side, but, the bearing life for some users has been questionable. Personally, I have had good luck with them.