I have an Ultegra Crank set. I also have a Deore XT 175mm left side power crank. Can I use this on a road bike?

  • 1
    If it's a Hollowtech II left arm, there's no reason I know of other than "it hits the chainstay" that it shouldn't work. But I don't have the time to actually research it, so this is just a comment. May 16, 2019 at 15:26
  • I suspect Q factor might be different. May 16, 2019 at 15:40
  • Would the Q factor different if they are both 175mm? May 16, 2019 at 16:10
  • Q factor depends on the shape of the crank, not just its length. (And, as an aside, can we have a real name for "Q factor", please? It's not a factor and it has nothing to do with the letter Q. It's about the worst name ever.) May 17, 2019 at 10:33
  • @DavidRicherby According to Wikipedia: The "Q" stands for "quack", a reference to the wide stance and waddling gait of ducks
    – Andy P
    May 17, 2019 at 11:30

1 Answer 1



Two considerations:

  1. Is the interface between the crank and bottom bracket the same? It seems they would be if both cranks have a Hollowtech II 24mm spindle. Googling pics of FC-R8000 and FC-M8000 cranks the interfaces look the same.

  2. Do the cranks have the same pedal offset from the axle? I.e., how far outboard does the crank arm push the pedal? You should be able to compare the crank arms directly.

  • At the moment I only have the power meter on the left crank. Will have to check the pedal offset..... May 16, 2019 at 16:47

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