will shimano un55 fit a 70mm bb shell?

ricardostan
ricardostan Posts: 3
edited April 2015 in MTB workshop & tech
I have a raleigh AT05. Im replacing the old bb and have managed to remove it from the shell. The shell width is 70mm. 2mm longer than the 68mm un55 from shimano. Will this new shimano bb fit in correctly? From looking at the pictures on chain reaction website, the thread doesnt go all the way to the outer rim of the non drive side on the bb. This means I dont know if it will fully engage with the bb when installed by being fully covered and slide inside the shell. Does anyone have experience with this problem or can offer advice? Thanks.

Comments

  • The Rookie
    The Rookie Posts: 27,812
    It will work fine, the driveside will screw all the way in and then the non drive side will do the same on the other side.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • RevellRider
    RevellRider Posts: 1,794
    Are you sure it is 70mm? That is normally for Italian bottom brackets and they have 2 r/h threads
    Alpha, Beta, Gamma, Epsilon.
  • ricardostan
    ricardostan Posts: 3
    RevellRider wrote:
    Are you sure it is 70mm? That is normally for Italian bottom brackets and they have 2 r/h threads
    Definite, measured again using a micrometer to be 69.4mm . Its not Italian thread either, the threads are different hands. I guess raleigh just make the shell a little larger than normal.

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