Back in the day, when I worked in bike shops, life was much simpler. If somebody wanted a replacement bottom bracket all you really had to worry about were whether the cups were English or Italian threads and how long the axle needed to be. There were some variations on the taper either ISO or JIS, but a quick check with a set of calipers in the workshop would soon identify which was needed.
Even when sealed unit bottom brackets became common place the same questions just needed to be answered. Unfortunately, Mr. Shimano then started getting ideas about changing the standards. Suddenly, we had to say hello to Octalink. The theory behind the design was good, but like all things Shimano it soon changed and then when it came to upgrading cranks or replacing a worn bottom bracket you had to check if the Octalink BB you were looking at was Version 1 or Version 2. This, of course, was in addition to square taper bottom brackets still being common place.
Then things started to get really complicated with the introduction of an alternative option to Shimano’s Octalink when the competition decided to launch the ISIS bottom bracket standard. So now there’s square taper, Octalink (V1 and V2), and ISIS to consider. Not wanting to fall behind in the development stakes, Shimano then moved the bearings outboard with the introduction of the Hollowtech II system. Still the only other concern, other than BB axle/crank interface, was the bottom bracket shell width and threads to think about, or so we all thought.
In order to make us buy more bikes and parts, manufacturers consistently invent new technology that we, the hapless consumer then falls for and spends money on. So it has been with the seemingly humble bottom bracket. For more years than anyone cares to remember the bearing in bottom brackets were held in place with cups that threaded into the frame, whether they were internal or external.
Cannondale saw this as an area where it could introduce change. In creating the press fit BB30, the marketing blurb stated that bearing life would be improved and the larger diameter axle would increase power transfer through increased stiffness. What the marketers failed to mention was the introduction of yet another standard, that also needed shops to invest in new tools to fit and service and that it would, if not carefully maintained, creak at every opportunity.
While Cannondale made BB30 open access, meaning anyone could use the design if they wanted to this was not enough for some in the industry so now the options for bottom brackets include not only all of those mentioned above but also SRAM’s GXP, PF30, BB86, BB92, and BB121 (these three are basically the same design, just different widths), Trek’s BB90 and BB95, and 386EVO.
There’s a similar situation going on with headsets too. Twenty-five years ago you has a 1in diameter, threaded headset. Simple. Mountain bikes heralded the introduction of 1-1/8in headsets and a short-lived trend for 1-1/4in headsets, and the birth of threadless headsets, which let’s face it was actually a real benefit. If it could have stayed like that we could all have been happy, but no. Today we’ve got tapered headtubes, semi-integrated and fully integrated headsets to contend with. Such is the bewildering choice of headset options that the likes of Chris King and Hope Technology offer online guides to help people select the right components for each individual application, and many manufacturers will allow shops to order a pick and mix of headset cups, which can then be used in conjunction with a suitable guide to outfit a bike, rather than buying a complete headset, so complex is the modern standard.
I’m so glad I don’t work in bike shops anymore. I think I’d lose the plot if a customer came in and asked for a new bottom bracket or headset and I was forced to go through 20 questions with them just to try and figure out what is was they needed.
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