Ive a specialized tarmac (2018) and want to convert from BB30 to shimano. I’ve been looking at Praxxis. But what one? Do I need OSBB to shimano?? What’s that?

Thanks in advance for any help

Just done one myself.
This page helped

https://praxiscycles.com/wp-content/uploads/PRAXIS-FRAME-GUIDE.pdf

You need to know what shell is in your frame, mine had circlips holding in the bearings type.

Once you I’d what you have it makes more sense

Hope do a nice conversion BB too.

I had the push in / no circlip type on my Spesh Camber and the Hope unit is a nice but spendy replacement. You will need to beg, borrow, steal or buy the Hope tool to fit it (and it makes bearing fitting a doddle).

Camber was probably pf30 with press in plastic cups containing the bearing rather than bb30.

Just work through the link above for praxis. You can change the bearings in the praxis cups when time comes with either hope or enduro ones

The Praxis ones come with a sleeve so it works with bb30 or pf30. Hope doesn’t make a bracket for bb30 to Shimano.

I have a brand new Praxis to fit the Specialized BB30 here that I’m willing to part with. I decided to use a BB30 crank instead on my build. Message me if interested.