MTB shimano deore front derrailour don't fit my new shimano deore triple crankset????

Discussion in 'Mountain Bikes' started by lennyz, Nov 11, 2013.

  1. lennyz

    lennyz New Member

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    I have just bought a new shimano deore crankset to my MTB. I already have a Shimano deore front deraillour, which fitted with my last shiman crank. The bottom bracket is a octalink v2. When i put on my new shimano deore triple mtb crankset. MY front derraliour cant get to the last chainring. I can se from my last crankarm, that the new deore chainrings are further away from the front derrailour. The distance from the from deraillour to my crankarms chainrings are longer than on my last crankset.

    I have never seen this before. Any ideers????
     
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  2. alfeng

    alfeng Well-Known Member

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    Yes. You probably chose the Octalink BB with the wrong spindle length ...
    AND/OR you have too many spacers on the driveside of the BB cartridge (the "required" number of spacers may be ZERO if your bike has an aluminum frame & the BB shell is 73mm wide) ...

    A quick CHECK is to see if the two crankarms are equidistant from their respective chainstays ...

    BTW. If your "old" crank had a square taper BB spindle AND it has a 118mm in length, then you were (unintentionally) deceived into choosing THAT length for your Octalink crankset.

    WWithout looking & due to an indifferent memory, I think the shortest Octalink V2 BB has a 113mm (?) length spindle & will solve your problem if it isn't resolved by removing unnecessary BB spacers.

    Without looking (again!), I am going to say that the distance which I once measured between the INSIDE face of the two crankarms of an Octalink V2 MTB crankset with a 113mm BB is 170mm ... BUT, that may have been the OUTSIDE (Q-Factor distance) measurement with the latter (outside distance) now seeming more likely so you'll probably have to subtract the thickness of the arms from that 170mm measurement.

    The reason I am mentioning THAT is because you want to ensure that a shorter BB spindle won't preclude mounting the crank ...

    So, if possibly removing unnecessary spacers doesn't solve the problem then MEASURE your bike before ordering the BB with the shorter spindle!

    FYI. I have mounted an XT crank on a bike with a steel frame (68mm wide BB shell & smaller diameter seat tube) with the short(er/est), 113mm Octalink V2 BB & I believe that the difference between the outward offset of the chainrings & a Road crankset's chainrings is ~5mm. That's like mounting a Road Triple crankset on a frame with the longer BB spindle which would typically be specified for a Triple Road crankset instead of a Road Double crankset on the particular frame.
     
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