Joined: Jul 2015
Posts: 7,159
Likes: 3,104
From: NW Oregon
Bikes: 1982 Trek 930R Custom, '91 Diamondback Ascent w/ XT, XTR updates, Fuji Team Pro CF road flyer, Specialized Sirrus Gravel Convert, '09 Comencal Meta 5.5 XC, '02 Marin MBX500, '84 Gitane Criterium bike
they aren't "rubber".it's neoprene, or something similar...
i've rebuild hundreds of such hubs, and they are still rolling fine.
i switched away from park grease years ago... i kept seeing a lot weepage from the stuff.
i use Maxima Waterproof Grease now.