Terry,
If the bottom bracket is Shimano Octalink use the
118.5mm spindle for both double or triple cranks with
the Octalink spline interface. Fit can vary when it
comes to bottom brackets with a square taper spindle.
I was using a Thorn triple with a Shimano square taper
bottom bracket that was only 107mm....a longer spindle
mover my chainrings out so far that the deraileur
didn`t have enough range to shift the chain onto the
big ring. I was using a carbon boom which did not have
the eccentric deraileur mount that the stock Baron
boom has that allows more range adjustability of the
front deraileur. As John said, sometimes a simple
washer or spacer behind the bottom bracket may be
used....it all depends on what components you are
using. On my NoCom, I have a 153mm Shimano 105 triple
crank, and I had to machine a 5mm spacer to move the
bottom bracket out far enough to be able to shift into
the granny gear. When I did this, I found that my
Ultegra 118.5mm triple bottom bracket didn`t have as
many threads engaged in the bottom bracket shell as I
would have liked, but I found that a triple Dura Ace
bottom bracket had a few more threads than the Ultegra
bottom bracket so that`s what I used. Since the 5mm
spacer I installed moved my spindle outward by 5mm, I
found a new problem....the left side of the spindle
was now shorter by 5mm and with the left crank
installed, the crank would now rub on the left bottom
bracket cup. I had to do some modifications to the
crank arm and cup to keep it from rubbing.....works
great now....

Don

--- Terry Pickl <newsletters4terry@...> wrote:

> Hello Everyone,
> Is there a recommended spacing for bottom brackets
> on the Barron?
> Typically diamond frames have 108mm bottom bracket
> for double (43.5mm
> chainline) and 118mm bottom bracket for triple (for
> 45mm chainline).
> Because of the boom, we don't need to be concerned
> about spacing frame
> issues. So I think we can use a shorter (smaller)
> spacing. But I know
> their there is issues with spacing on a dropped
> chain.
>
> I plan on running the chain through the idler
> wheels. Someday when I
> get comfortable with pedaling the bike, I might drop
> the chain.
>
> Thanks,
> Terry
>
>
>
>
>


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