# Ultegra 6800 crank on OSBB?



## lostPixels (Jun 12, 2012)

I'm about to buy a 2014 Roubaix SL4 Sport and upgrade it to full Ultegra 6800. I've read that the Ultegra crank is not compatible with OSBB, and that I will need an adaptor. According to a thread here from 2011, using BB adaptors will void your frame warranty. Anyone know if that's still a fact?

Anyone that has done this sort of thing, please let me know your experiences. Thanks!


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## MMsRepBike (Apr 1, 2014)

You've read wrong.

OSBB is a frame standard, it's just a hole. Ultegra is a 24mm spindle crank, it can fit in that hole with zero issues.

You need to find out something about your bike. Does it have a real OSBB like mine does or does it have a metal insert to make it a BB30? My bike is just a carbon fiber hole, that's it. No metal or anything, just a hole. That is what OSBB is. Many Specialized frames that have this OSBB hole have an insert put in it to hold c-clips and bearings to make it a BB30 setup.

In either case, Praxis works makes a conversion bottom bracket for you. I have their OSBB one in my Tarmac and it's perfect. I have the Ultegra crank in it, it's made for it.

http://www.praxiscycles.com/wp-content/uploads/PRAXIS-FRAME-GUIDE.pdf
Read this first. Be sure of what frame you have. Go down to the bottom for OSBB guide.

Pick the right one and make sure a shop installs it correctly. Force them to read the instructions and install it with the instructions handy. Be there for it if you can, make sure it's done right. It's easy but it's easy to mess up.

This should set you straight with zero warranty issues, but you know... Specialized...


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## robt57 (Jul 23, 2011)

MMsRepBike said:


> You've read wrong.
> 
> OSBB is a frame standard, it's just a hole. Ultegra is a 24mm spindle crank, it can fit in that hole *with zero issues.*


*

'zero issues' ? A lot of threads seem to show otherwise...

Due respect and all...*


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## MMsRepBike (Apr 1, 2014)

robt57 said:


> 'zero issues' ? A lot of threads seem to show otherwise...
> 
> Due respect and all...


The issues aren't with the crank fitting the bottom bracket hole, it's with what's between them. Put a Praxis between them and there won't be any problems. Use some crap adapters and a BB30 sleeve or whatever and you'll find nothing but issues.


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## lostPixels (Jun 12, 2012)

The other thing that I just realized is that the 2014 Roubaix Sport has an FSA BB30 already included. I may not need to buy a Praxis BB after all... Ideally, I can just replace the crank with an Ultegra 6800 without having to take on BB assemblies. 

2014 Specialized Roubaix SL4 Sport 105 - BikePedia


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## MMsRepBike (Apr 1, 2014)

Not so. Shimano doesn't make any BB30 anything.

You will need to find out if your BB30 shell has removable c-clips or not. It should.

You will still need that Praxis 68mm Shimano conversion bottom bracket to make it work.


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## TricrossRich (Mar 26, 2014)

Agree 100% with what MMsRepBike is saying... Praxis all the way. The Ultegra crank set will NOT fit with what's currently in there. With the Praxis, everything will work perfectly.

I have Ultegra 6800 installed in my OSBB Allez Comp and DA9000 in my OSBB Venge Pro.


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## robt57 (Jul 23, 2011)

MMsRepBike said:


> The issues aren't with the crank fitting the bottom bracket hole, it's with what's between them. Put a Praxis between them and there won't be any problems. Use some crap adapters and a BB30 sleeve or whatever and you'll find nothing but issues.


Well I don't know what is crap according to your experience/opinion. I have a SL4 Roubaix that I used the OSBB to 24mm adapters that came with the bike new. I did have some pops early on, but when I pulled the Sora HT-II cranks for both 6650 and 7800 I have gone back a forth a few times between, I have no issues after I started using little silicon O-Rings outside the adapters, pops gone, zero issues. Of course reading your posts here in this thread would lead one to think this is not possible without spending more money on a Praxis or other BB system beyond the adapters. I can empirically say this is not the case.


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## Dunbar (Aug 8, 2010)

How many miles on your adapters? My first set didn't start making noise for 2500 miles. The second set started making the crackling noise around 1000-1500miles. Praxis is a good option, just make sure you're getting the latest version with aluminum cups that sit between the crank and adapter. I had the original Praxis adapter replaced under warranty.


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## robt57 (Jul 23, 2011)

Dunbar said:


> How many miles on your adapters? My first set didn't start making noise for 2500 miles. The second set started making the crackling noise around 1000-1500miles. Praxis is a good option, just make sure you're getting the latest version with aluminum cups that sit between the crank and adapter. I had the original Praxis adapter replaced under warranty.


My started making like a PITA pretty quick. Less than 500 miles on the bike now. And it won't see 2500 miles with me on it, selling it when my Custom gets here...


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## lostPixels (Jun 12, 2012)

Instead of buying a Sport model, I am just going to go for the comp that has 11-speed Ultegra already on the bike. It's more money than doing it myself, but I am not confident in my abilities to build it up lol.


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