it limits how wide you can make the frame and suspension pivot, bad for stiffness-to-weight ratio. It works for road since they have narrow chainstays and want to keep the downtube somewhat narrow and aero. If you compare a PF92 frame like a new Scott (same width as a BB386 would be if done on a MTB) to a BSA frame like Santa Cruz the difference in the width of everything around the BB is massive. What frame designer wouldn't want that room to work with?Why is pf30 too narrow? I just installed a bb386 crank into a PF30 BB with the appropriate adapters. My understanding is the bb386 is PF30 with an extra10mm on each side. Why not have the option if you wanted a narrower q factor?
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