B
Barnard Frederick
Guest
I have a MTB frame that I want to put a compact road crankset on.
Actually it is a Cannondale Bad boy (stupid name, I know) that is a
kinda sorta hybrid. I found that external bearing cranksets have a
limitation that I didn't know about: it doesn't appear that you can do
any tricks with the chainline. If you buy a road crankset, you will get
the chainline, usually 43.5mm, that is inherent to the design. A MTB
outboard bearing crankset has spacers, but they are only there to
compensate for a the differences between 68mm and 73mm shells. Due to
the design of the assembly, it doesn't look like there is a way to play
with the chainline at all. I would love to hear that I am wrong on that
subject.
So, like many other MTB frames, the 43.5mm chainline on this bike comes
too close to the chainstays for comfort. I haven't actually tried it
yet, but I really don't want to learn the hard way. Cannondale tech
said they didn't think it would work and my measurements haven't been
encouraging. The other option which looks like it may work is to use an
Octalink or Isis crankset and instead of using the 108-109mm BB for
doubles to get the 43.5mm chainline, use a 118mm BB designed for triples
to get the chainline back to about 48mm. Opinions?
Actually it is a Cannondale Bad boy (stupid name, I know) that is a
kinda sorta hybrid. I found that external bearing cranksets have a
limitation that I didn't know about: it doesn't appear that you can do
any tricks with the chainline. If you buy a road crankset, you will get
the chainline, usually 43.5mm, that is inherent to the design. A MTB
outboard bearing crankset has spacers, but they are only there to
compensate for a the differences between 68mm and 73mm shells. Due to
the design of the assembly, it doesn't look like there is a way to play
with the chainline at all. I would love to hear that I am wrong on that
subject.
So, like many other MTB frames, the 43.5mm chainline on this bike comes
too close to the chainstays for comfort. I haven't actually tried it
yet, but I really don't want to learn the hard way. Cannondale tech
said they didn't think it would work and my measurements haven't been
encouraging. The other option which looks like it may work is to use an
Octalink or Isis crankset and instead of using the 108-109mm BB for
doubles to get the 43.5mm chainline, use a 118mm BB designed for triples
to get the chainline back to about 48mm. Opinions?