Square taper to Isis

The Rookie
The Rookie Posts: 27,812
edited October 2010 in The workshop
My daughter is currently commuting on her Hybrid buiilt Claude Butler trailridge, running a square taper BB with Shimano cheapy (Rivited C/W) CHainset.

She has some tasty Truvative Elita isis cranks and wheels to go on, we've already found her a trouser guard (she commutes to school in Jeans) in place of the larger chain ring, so she'll be using the inner two wheels (42/32 sothe same as the larger and middle of the current triple).

Want to sort her the BB for Christmas (to go with the trouser guard she doesn't know we have), the square taper on there is 113mm, so what width do we need, 113 (assuming distance from end of BB to middle wheel is the same square to ISIS) or something different? I want to keep the middle chain wheel in the same location as the current MTB middle as she only really uses the biggest wheel on her current commute.

Simon
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.

Comments

  • The Rookie
    The Rookie Posts: 27,812
    Anyone?

    Simon
    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.
  • rjsterry
    rjsterry Posts: 29,811
    Square taper and ISIS BBs use the same basic principle - crank bolted into the end of the BB axle - then I would expect you to need the same length of BB axle.

    Sheldon has a page on BB sizing

    http://sheldonbrown.com/bbsize.html
    1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
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  • The Rookie
    The Rookie Posts: 27,812
    Thaks for that, had looked on PT and sheldon, must have missed it, looks like Truvative Isis after shimano square will move the chainline out 5mm on the same BB size, so will stick to 113mm on the basis 5mm will make sure the larger inner wheel clears the frame!

    Simon
    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.

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