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I have a Specialized Tarmac Sport 2017 with Praxis M30 bottom brackets. These I think are BSA threaded on both sides, 30mm and 28mm. 

I mistakenly bought Praxis BB30 to Shimano adapter 24mm, which is threaded on one side and push fit on the other! 

Which adapter/bottom bracket will I need to run Shimano Ultegra r8000 cranks?

 

Cheers

 

3 comments

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VeloUSA [272 posts] 3 weeks ago
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Pretty sure your Specy BB is threaded on one side. Remove your cranks and check. If threaded the standard Praxis BB30 will work.  https://praxiscycles.com/product/standard-bb/

If it's not threaded then you'll need this one.  https://praxiscycles.com/product/shimano-conversion-bb/

 

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Mockyyy [1 post] 2 weeks ago
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Thanks for your reply. 

It's threaded on both sides. 

https://praxiscycles.com/product/m30-english-threaded/

This is the BB currently installed. Both sides are threaded. 

Just want to double check since the shimano-conversion in your second link is not the right adapter. The first link "standard Praxis BB30" looks similar sized to shimano bottom brackets which are natively 24mm. 

Here's the bike, it only says "Threaded BB" :

https://www.specialized.com/us/en/tarmac-sl4-sport/p/115443

 

Cheers

 

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Jimmy Ray Will [970 posts] 2 weeks ago
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I'd suggest you need a standard bottom bracket if it is stating that the current BB is english threaded. 

I bought a new Allez for winter this year and was surprised that the Praxis 30mm axle was being held by a Praxiz 30mm screwed bottom bracket, but that bottom bracket was indeed standard english threaded. 

Awesome times.