I haven't replaced the BB. So far I'm very happy with my conversion. I've been riding it every day (with a 120 hub in my 126 frame). Now that I'm sure I want to stick with fixed gear riding, I'm trying to decide the best way to upgrade the whole rig for the long term and simultaneously work out a few of the kinks such as a friction which I believe is caused by a slightly off chainline. At the moment I'm debating between getting a properly spaced 126 hub (and a new BB?), or saving up for a new frame with 120mm track ends to accomadate my existing hub et al (i guess i may still need a new BB). I was looking at maybe the IRO Mark V (other suggestions in same rough price range?). The advantage of just getting a new hub is that it would obviously be cheaper and i DO really like my Fuji frame, but getting a dedicated fixie frame may be a better long term strategy.