Fitting a 24mm crankset to a Cannondale BB30a road frame

letmetalktomark

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Hopefully this is a simple one but in reality it never is!

I’ve seen, what I think, is a good deal on a new Cannondale carbon (road) frame set (no BB)

Allowing a bit of extra money for a 25.4mm (!!) seat post I have a full build kit of bits … but it’s all Shimano 105.

Can you just fit a BB30 to 24mm bottom bracket? Is there anything special offset wise ( this isn’t an AI frame as far as I know) that I need to be aware of?

I’d ideally like a threaded BSA frame bur paupers can’t be choosers 🤭

All help much appreciated.

Posted : 06/02/2026 7:00 pm

bikerevivesheffield

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https://www.cannondalespares.com/Wheels-Manufacturing-BB30-to-24mm-Crank-Spindle-Shims--68mm-frame--Shimano/product_detail/3-40259

Posted : 06/02/2026 7:36 pm

bikerevivesheffield

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https://www.sjscycles.co.uk/bottom-brackets/wheels-manufacturing-bb30-to-outboard-bottom-bracket-black-24mm/

Posted : 06/02/2026 7:37 pm

johnnystorm

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https://r-uk.co.uk/v1.asp?prd=240382&cat=1054&ms1=GS1&gad_source=1&gad_campaignid=17307547373&gbraid=0AAAAAD-eY4kmB6vNB_feDgMlI9Ve1hXK5&gclid=CjwKCAiAv5bMBhAIEiwAqP9GuHX0lwPOlDcRKlGlbScV3ExDkyQrPfUAojqhSO014SIEKEpDBOXSIhoCe8kQAvD_BwE

https://ebay.us/m/8m2Gc8

Posted : 06/02/2026 7:51 pm

letmetalktomark

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Thanks folks.

Does it make a difference those are all BB30 and not BB30a?

(stoopid standards)

Posted : 06/02/2026 8:00 pm

bikerevivesheffield

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No to the first one

https://www.bikeparts.co.uk/products/wheels-manufacturing-bb30a-to-outboard-btm-bracket-for-24mm-shimano-cranks-black

Posted : 06/02/2026 8:02 pm

susepic

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the threadfit wheelsmfg bb30 to 24 is almost certainly the right answer (but not sure about the asymmetry thing - guess spacers on the NDS required). I have been running one in my roadbike for the last 3 years and it is fault- and creak-less

Posted : 07/02/2026 1:17 pm

boblo

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I use both the Rotor and Wheels BB30 to 24mm adapters with no issues. There's at least 5mm adjustment via the threading where the two sides join so I can't see the 68mm vs 73mm BB30 vs BB30a being an issue. However, if you're a bit uncertain, just buy that type of adapter advertised for use with BB30a - you'll be grand.

Posted : 07/02/2026 1:48 pm

Speshpaul

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I’ve got a pair of the bb30 to 24mm adapters as above

make me an offer👍

Paul.sal@btinternet.com

Posted : 07/02/2026 4:12 pm

letmetalktomark

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Thanks again all.

@speshpaul … if I had a BB30 BB to start I’d take you up on that 😊

Posted : 07/02/2026 4:29 pm

bikerevivesheffield

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https://www.superstarcomponents.com/products/bb30-press-fit-bottom-bracket-skf-or-ceramic-bearings?variant=55089386094977

Posted : 07/02/2026 7:12 pm

dovebiker

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FWIW BB30A is asymmetric, so 5mm wider on the NDS so need to determine whether your 24mm crank spindle is long enough to work?

Posted : 07/02/2026 8:12 pm