Originally Posted by
carleton
The BB-7700 is the needle bearing model. BB-7710 is the NJS sealed bearing model.
NJS racers are required to race in the rain which makes the sealed bearing model (7710) more practical.
http://www.youtube.com/watch?v=AB0cYVQEEWY
The needle bearing model (7700) can be tuned to spin more smoothly than the sealed model using tension (or lack thereof) on the bearings and your choice of lubricant. But, this one needs the routine maintenance than all ball bearing hubs require.
So, I guess use the 7700 on the indoor / special occasion bike and use the 7710 on the outdoor / training bike.
If you grease and install the 7700 right, with the backsides of the outer additional plastic bearing shields loaded with grease, and placed to make a labryrinth sealing with edges meeting the outer lips of the alloy right and left cups, you get Better sealing for outdoor road use than that 7710 track model, which has free running seals that are not resistant in outdoor settings