Rotor conversion BB with C'Dale crank?

Discuss light weight issues concerning road bikes & parts.
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FastforaSlowGuy
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Joined: Fri Dec 30, 2011 10:02 pm

by FastforaSlowGuy

I'm sure this has been asked before, but I can't find it. Has anyone tried to use a Cannondale hollowgram with the Rotor BB (the one that allows use of their BB30 crank on a BSA bike)? I thought I read somewhere the axel length is off, or something.


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bikerjulio
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by bikerjulio

You will have to do some research on spindle lengths available with the Cannondale, but I strongly suspect the answer is "no".

Currently there is what is effectively a "long BB30" standard evolving, otherwise known as BB386EVO. It uses a 30mm spindle but with the bearing spacing of a 386BB. (Which is derived from a regular old fashioned BSA BB with outboard cups). Right now FSA, Rotor and Campagnolo make these cranksets, possibly others too. It's a flexible solution for a wide variety of BB shell types, including BSA.

A "regular" or standard BB30 system puts the bearings closer together and uses a shorter spindle, which is probably what you have, although you need to be more specific about what crankset you have.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

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TimmS
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Location: Amsterdam

by TimmS

Yes it can be done. You need a longer spindle and modify it a little bit.
If I remember correctly you need a 122 mm spindle.
As a result your chainrings will be 9mm more outward and the q-factor will be 18mm wider.

If you don't care about this it will be perfectly fine.

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bikerjulio
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Location: Welland, Ontario

by bikerjulio

TimmS wrote:Yes it can be done. You need a longer spindle and modify it a little bit.
If I remember correctly you need a 122 mm spindle.
As a result your chainrings will be 9mm more outward and the q-factor will be 18mm wider.

If you don't care about this it will be perfectly fine.


This illustrates another problem - primarily chainline and to a lesser extent the Q factor.

These problems would not be there in a "BB386EVO" type crank which would provide the correct chainline. I'm not sure you could get a FD that would work with a crank 9mm further away, plus the undesirable chain angles that would occur.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

eric
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Joined: Tue Nov 11, 2003 9:47 pm
Location: Santa Cruz, California, USA
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by eric

The bad chain line and Q factor make the Cannondale conversion a non starter.

Sram Quark BB30 cranks are "long BB30". So are Lightning.

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