I have no answer. But I have size 13 feet, 175 crank arms. on a Volpe with 435 mm cst. and a rack that goes back 15 in. from the seat stay braze on. I can clear Nashbar MTB panniers or Jandd lg mtn . bags. Jandd 's expedition rack goes back 18 in. from the braze on. so this would give you even moore room, than I have. Good luck with your rear spokes!