They aren't. It's some odd cup and cone thing with needle bearings. They might be "sealed" with an O ring, but its definitely misleading.
A 7710 is just a 7700 with an NJS stamp.
http://bike.shimano.com/media/techdo...9830610606.pdf
http://bike.shimano.com/media/techdo...9830646804.pdf
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Originally Posted by
seau grateau
No offense but you're an idiot.
PedalRoom