Shimano STX FC-MC31-CH Triple Crank Arm (Right Only!)


When we see parts that are unique and hard to find we pick them up so you don't have to search the globe.  This is a bit of an odd duck as far as crank arms go.  It is a Shimano STX FC-MC31-CH Triple Crank Arm - Special Edition in a cool brushed nickel/bronzish colour.  Likely if you are reading this you already have one and need to replace it. Otherwise setting it up will be challenging.

First of all it has only one set of ring bolt mounts (58mm).  The granny and middle bolt to the bolt mounts separated by the appropriate spacer.  The middle ring is unique in that it has holes to bolt a large ring. The large ring then sits at the edge of the five arms of the crank spider and bolts to the middle arm separated by spacers. To and one more challenge the large has a BCD of 95mm not 94mm as is standard.  So, thus, only one middle and large ring will fit this crank arm. I believe it to be compatible with other crank arms and rings of the STX group with part numbers FC-MC31, FC-MC32 and FC-MC33 with the extension RC or CH.

But it is beautiful!

Now I haven't explored all the alternative way of setting this up, but go crazy!

  • Square taper
  • 175mm crank arm length
  • C. 1993/1994
  • Made in Japan