bottom bracket help

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bottom bracket help

Postby davehirst » Wed May 30, 2018 3:18 pm

I have purchased a second hand cannondale super six evo frame, and have a few questions.
Firstly the bottom bracket assembly, there are no aluminum cups or sleeve for the bb, just a ridge around the id of the carbon frame.
the id is46mm and shell width is 68mm. does this mean the bb goes straight against the carbon or should there be a sleeve.
From my research i thought it was pf30. I think i would like to run hollow tech cranks, or would praxis cranks make it easier
I noticed the praxis works bb converter has a plastic sleeve, would this glue to the carbon shell, .
Secondly i have an easton sl carbon fork of 1 1/8 straight steerer, is it feasable the use a reducer race to bring down the 1.5 head tube down to 1 1/8, I have one of these on a MTB and it seems ok.

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Re: bottom bracket help

Postby Duck! » Wed May 30, 2018 10:01 pm

68x46 is PF30. There doesn't have to be an aluminium liner sleeve, because like BB86 press-fit, the bearings are housed in plastic cups which are pressed into the frame. This distinguishes it from standard BB30, which has the bearings direct-fit into the frame.

Praxis Works do produce a bottom bracket adaptor to allow fitting a Shimano-type crank into a BB30 shell, but I am not sure if it is compatible with the larger bore PF30 shell. If it isn't, there are other spacer kit options which fit into the standard PF30 bottom bracket installation to enable shimano-type cranks to be fitted.
I had a thought, but it got run over as it crossed my mind.

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Re: bottom bracket help

Postby macca33 » Thu May 31, 2018 8:54 am

Yep, as Duck mentions - it is PF30.

Praxis works does an adapter which will press-in to the BB shell and provide for 24mm bore to suit Shimano cranksets.

Also, Wheels Mfg do a cheaper option - a pair of Delrin spacers which press into the 30mm PF30 BB and the adapters have a 24mm bore to suit Shimano cranksets.

Plenty of options are available. No need to 'glue' anything in.

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Re: bottom bracket help

Postby davehirst » Thu May 31, 2018 5:30 pm

Thanks for the replies

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Re: bottom bracket help

Postby Bentnose » Sun Jun 17, 2018 6:38 pm

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