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by James Huang
October 21, 2016
Photography by James Huang
Creak, creak, creak…
Too many riders with press-fit bottom brackets are all too familiar with that irritating sound, emanating from down below and repeating itself at 90rpm every time you head out for a spin. While press-fit systems can (and often do) perform flawlessly, horror stories abound with tales of ruined frames, cups permanently secured with two-part epoxy adhesives, and annoying sounds that just won’t go away no matter what.
T47, on the other hand, is a new threaded bottom bracket system introduced last November that uses a standard 68mm shell width, but a oversized 47mm internal diameter. The threaded interface decreases the incidence of creaking and eases at-home maintenance, and the wide range of available cup options makes it compatible with virtually every crankset on the market — including narrow-format BB/PF30.
In addition to accommodating 30mm-diameter spindles, T47’s oversized bottom bracket shell also provides frame engineers with more design freedom than the traditional English-threaded standard.
In addition to using a threaded interface, T47 is also highly adaptable. The bottom bracket in the background uses 24mm-diameter bearings in a wide format for Shimano or SRAM GXP cranksets, for example, while the one in the foreground houses 30mm bearings inside the shell for narrow-format BB/PF30 cranksets. Both fit in the same frame.
Originally developed by Chris King, Praxis Cycles, White Industries, and Argonaut Cycles, the system has since found additional support from the likes of Wheels Manufacturing, Enduro Bearings, Engin Cycles, Kent Eriksen Cycles, and countless other bottom bracket specialists and smaller frame builders. Yet almost a year after T47’s introduction, the industry hasn’t exactly embraced it with open arms, or even openly praised the merits of the concept. But why?
US technical editor James Huang sits down for this week’s CyclingTips podcast with Adam Haverstock of Praxis Cycles, Chuck Panaccione of Enduro Bearings, and Jonas Johnson of Chris King to discuss the pros and cons of T47, the politics surrounding its implementation, and how we ended up here in the first place.
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Episode 15 Direct Download