It's pretty good. But most people find it cumbersome (in terms of maintenance required) for whatever real or perceived benefit(s) it provides. Bike shop owners often report changing out the DA BB for an Ultegra BB. The Ultegra is much more weather-resistant, do not require frequent maintenance (nor is it even possible to do so on the Ultegra unit), and cost less. The only drawback is the Ultegra unit weighs a bit more.

I have a DA7700 crank, and have both DA and Ultegra Octalink-1 BBs. Unless it is on my special-event bike that I seldom ride, and I need the BB to match (important for some), I'll throw on the Ultegra BB. I find myself overhauling the DA7700 BB every 2000 miles or so of dry-weather riding. Riding the bike, I cannot tell the difference between the models.


On this, I disagree with greyghost_6.

The DA7700 BB needs a properly faced and chased bottom bracket. The design has the spindle as the race for the roller bearings (which presumably takes up most of the load). As such, if the two cups are not aligned, the BB will bind. The center plastic piece is only a weather-proofing part so it is not going to align the cups.

As a comparison, the Ultegra BB is a single cartridge unit, not unlike the older Shimano UN-72. In such a design, the left cup is only an "end stop" so alignment of left and right cups are not so critical.


I wouldn't. I don't believe the balls (small as they are) are loaded highly. So there's really no reason why one would add extra balls to the original design.


The balls are to locate the spindle because the roller bearings cannot support an axial load. I believe roller bearings are used in this design because the spindle diameter is really quite large for an inboard BB so there isn't much space to put in balls that are large enough for the intended loads; for the same "head space", roller bearings support radial loads better than ball bearings.