Bottom bracket “standards” have never been standard
When Shimano, followed in rapid succession by FSA and SRAM, came out with its first integrated-spindle crankset with external bearings, it took the bike industry by storm and put countless small crank makers out of business. But it was not the first such revolution.
A decade prior, Craig Edwards (now of EE Cycleworks) had come out with his integrated-spindle Sweet Wings cranks, which had an external bearing threaded cup on the non-drive side and a more standard cartridge-bearing cup on the drive side. The Sweet Wings also anticipated Campagnolo’s Ultra-Torque cranks, because, like those, it had a section of spindle integrated into each arm that bolted together in the middle.
Sweet Wings also preceded the SRAM GXP design and featured a shoulder on the spindle, which indexed from the inboard side of the bearing to fix the lateral position of the crankarm. That is merely one example of how we’ve seen almost every crank and bottom bracket design before, at one time or another. The Look ZED is perhaps the most futuristic crank these days, with two arms and 50mm-diameter spindle made into a single piece. The system is analogous, however, to the Ashtabula one-piece cranks that people 55 and older all had on their first bikes. The only things unique about the French system may be dimensional: the 65mm inside diameter (I.D.) of the bottom bracket shell, adjustability to three different crank lengths, and the spider arms that have both compact 110mm and standard 130mm bolt circle diameters (BCD).
Threadless bottom brackets with press-in bearings are now the norm on high-end bikes, but they have appeared over and over in the past. The Ashtabula is one example, using loose-ball bearings, as are the more recent bottom brackets from the 1980s utilizing cartridge bearings and snap-rings found on some Fat Chance, Klein, Fisher, Ritchey, and Merlin bikes. Many different thread diameters, pitches, and directions have been tried over the years.
As new crank and bottom bracket designs come out, don’t be surprised to find yourself wondering, “Haven’t I seen something like this before?” —LENNARD ZINN