Product Design: Pressfit 30 Bottom Bracket System

July 10, 2012

in Bike Design, Engineering, Product Design

Were adding yet another bottom bracket system to Seven’s offerings.  Up until now we’ve only offered:

  • 68mm English Thread Bottom Bracket:  Classic standard for many years
  • Eccentric Bottom Bracket:  Primarily for single-speed bikes and tandems
  • BB30 68mm Bottom Bracket

Pressfit 30 sketch and cartridge

But, golly, that’s not enough options so SRAM is offering a Pressfit 30 alternative to BB30.  The Pressfit system solves some of the issues of the BB30.  But then again, so does a standard English threaded shell.

Project timeline in reverse:

February 14  |  The first two Pressfit 30 bikes are going through Seven’s production system right now.  Someone asked, “What’s the big deal, it’s pretty much a BB30 system, right?”  Sort of.  It only requires:

  • A different starter tube size
  • An entirely different shell design and size
  • New fixture adapters for machining, tacking, welding, finishing, and paint
  • A new cutter diameter for adjoining tubes
  • A new CNC program for post-weld reaming, facing, and counter-boring
  • An new go-no-go gauge for the final ream size, along with a new set of standards for tolerances
  • Some new testing standards

January 31, 2013  |  Getting the SRAM Pressfit 30 bottom bracket “system” into production.  Super psyched that there’s yet another BB system to which we’ll adapt.  I do like that this system tries to fix some of the issues that can arise with a classic BB30.  It’s almost like a regular bottom bracket, without the threads.

July 10, 2012  |  The Pressfit 30 bottom bracket system is back on the Seven Cycles development list.  It keeps going away and coming back.  This time I believe it’s here to stay.  We’re looking at material requirements, CNC programming shenanigans, and long-term durability studies.  Thinking about doing a fatigue test.

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