I got my motobecane partially disassembled and I did all tuning and alignment myself. Being a new joiner it makes me feel I am missing some point. The issue is when my bike is on the stand the shifting is smooth for all 3x8 gears, but when I seat or especially drive with bouncing I cannot reach lowest 2 gears in the rear or they jump up and down. Adjusting b-screw seems helped a bit or this is just my impression. Shall I look into rear scock initial preload? Looks like my sag is too big?

  • 2
    The problem may be frame flex, causing the path of the shift cables to change in length as the bike bounces. – Daniel R Hicks Jul 16 '18 at 2:17
  • Frame flex? No way, this is brand new frame and I didn’t have a chance to ruine it yet. It happens when rear shocks get into initial sag state – Viktor Stolbin Jul 16 '18 at 15:31
  • If the rear wheel is on shocks, that is definitely "frame flex". – Daniel R Hicks Jul 16 '18 at 15:34
  • "It happens when rear shocks get into initial sag state." So, when you check the cable housing, at the ends where it's mating with a socket on the frame or derailer, does the housing tend to pull out a bit as the shocks flex? – Daniel R Hicks Jul 16 '18 at 16:11

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