Last year I heard that Dura Ace had upgraded their bottom brackets to a new design needing less maintenance. I bought a couple from one of the big suppliers.
Today I finally got around to replacing the DA bottom bracket on my five year old road bike which has many thousands of miles on it. I had no particular reason to replace it, it just seemed to be overdue. As far as I could tell, the old BB was identical to the new one. I am very confused. They are both labeled BB-7700. Both BBs required that special wrench that locks into those eight teeth cut out of the lock rings.
Did I get the old design BB? Is it hard to tell the difference? Does anyone know what I am talking about?
Since it is still an unsealed bearing BB, about the only thing they could have done to make it less maintenence is doing something about that crappy rubber seal. Of course, while my impression of maintaining a DA BB relates directly to dirt in the bearings, shimano’s idea may mean something totally different but it still relates to the maintaining of the BB on some obscure and non-functional way (i.e. not keeping out grit and water).
Plus, I never heard they changed it, so I can’t really be any help.
I didn’t look closely, but the rubber seal may have been different.
I guess I shouldn’t complain. I got five years out of the old one, and I may well have been able to get five more years. I just changed it because I felt guilty.