The external cup design allowed bearings and spindles to grow in size, but with the frames’ bottom bracket shells growing in diameter and sometimes width too, these external cups are becoming a thing of the past.
Although Specialized’s FACT crank shares the same spindle and bearing diameter as the BB30, it was designed in tandem with their OSBB frame design. The proprietary design is in stark contrast to Cannondale’s approach of leaving BB30 as an open standard. Cannondale’s Hollowgram crank is still one of the lightest and stiffest BB30 options available, and also one of the most expensive, coming in at $845.
Look doesn’t play by anyone else’s rules with the one-piece, hollow, ZED crank, which uses a 65mm-diameter bearing that is housed within the frame. The hollow crank and large bearings are a perfect example of a proprietary design.
One of the latest bottom bracket standards released is the BB386EVO, which was a joint effort between FSA, BH and Wilier.
Since the bottom bracket is the frame’s nucleus, it’s not surprising that there have been so many different ideas of the perfect system.