Old 04-03-18, 11:43 AM
  #31  
fietsbob 
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FWIW, Schlumpf, 1.6x overdrive 2 speed geared cranks use the similar chamfered edge BB Shell modifications.

they're an integrated BB gear box combination .. a 34t chainring acts like a 54, in its overdrive range ,
chainring turns faster than the crank-arms.. but at same rate in low..

Threaded within themselves, to compress against the conic ends but not into the frame threads....



....

Last edited by fietsbob; 04-03-18 at 11:50 AM.
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