HOT: Active* forum members generally gain 5% discount at starbike.com store!
Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Articles FAQ Contact About




Post new topic Reply to topic  [ 23 posts ] 
Go to page Previous  1, 2
Author Message
PostPosted: Wed Sep 18, 2013 12:17 pm 
Offline
User avatar

Joined: Fri Dec 11, 2009 10:38 pm
Posts: 1073
Location: Toronto
Herb5998 wrote:
68x42 is the Original BB30 Standard, using Circlips and 61806 Bearings. 68x46 is the PF30 Standards, using press in cups (46mm Diameter) with bearings installed in the cups. Measure what the ID of your BB Shell is and that will tell you what you need to use.


Unfortunately, Spec's carbon OSBB is a variation on PF30. The bare shell is 61mm wide x 46mm ID, whereas a "standard" PF30 shell is 68mm wide. Spec's press-in cups then space the BB out to 68mm by having a 3.5mm thick flange.

This explains the OP's problem as well.

_________________
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM


Top
 Profile  
 
Posted: Wed Sep 18, 2013 12:17 pm 


Top
  
 
PostPosted: Wed Sep 18, 2013 5:13 pm 
Offline

Joined: Thu Jan 21, 2010 4:18 pm
Posts: 84
Location: phoenix, az
Thanks, and that makes sense. What is still very unclear is which models have the carbon osbb that is 61x46 and needs press in cups, and which have the alloy osbb that is 68x42 and requires circlips. Specialized seem to have conflicting documents as to which my frame (2011 tarmac sl3 pro (sram)) has. Is there an easy way to determine this, specifically while the current specialized crank is installed?

I think I have now come to the conclusion that a bb30 crank (rotor 3d+ power2max) is the correct option, but want to make sure I have or order the correct clips, cups, etc. Is it the case that I can just use the cups or clips that are on the current specialized crankset, or is it best to start fresh?

Also along those lines, although I am not experiencing any issues with my original bb, when I go to install the new crank, is it a good idea to do a new bb/bearings? My bb is original and has roughly 20,000mi on it, has been cleaned/greased periodically, and seems to still spin smooth, but I'm not finding very clear information on typical bearing life span, and am thinking that if the degradation of the bearings happens over such a long period of time I may not necessarily know that they are that worn until I feel new bearings.

Thanks for your help, I'm probably over thinking some of this, but just want to make sure I do this right.


Top
 Profile  
 
PostPosted: Wed Sep 18, 2013 5:19 pm 
Offline

Joined: Sat Jul 29, 2006 2:36 am
Posts: 1161
Location: UK
I was about to post the Spec OSBB document but you've beaten me to it. Have you posted the same link twice?

The easiest way to check what you have is to turn your bike over and measure the width of the bottom bracket shell (frame only, don't include any cups) with a ruler. 61mm means it's carbon.


Top
 Profile  
 
PostPosted: Wed Sep 18, 2013 5:55 pm 
Offline

Joined: Fri Oct 21, 2005 4:08 am
Posts: 258
if it has a alloy bb shell, its 68X42 (BB30), if it's full carbon, then it's 61X46 (specialized's pf osbb)


Top
 Profile  
 
PostPosted: Wed Sep 18, 2013 6:39 pm 
Offline
User avatar

Joined: Fri Dec 11, 2009 10:38 pm
Posts: 1073
Location: Toronto
With the PF30 version of OSBB you will clearly see the cups protruding 3.5mm from the face of the frame.

like this

A regular BB30 frame has no protruding bits, the bearing sits flush with the face, with just a bearing cover.

_________________
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM


Top
 Profile  
 
PostPosted: Wed Sep 18, 2013 6:39 pm 
Offline
User avatar

Joined: Fri Dec 11, 2009 10:38 pm
Posts: 1073
Location: Toronto
With the PF30 version of OSBB you will clearly see the cups protruding 3.5mm from the face of the frame.

like this Image

A regular BB30 frame has no protruding bits, the bearing sits flush with the face, with just a bearing cover.

_________________
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM


Top
 Profile  
 
PostPosted: Wed Sep 18, 2013 8:31 pm 
Offline

Joined: Thu Jan 21, 2010 4:18 pm
Posts: 84
Location: phoenix, az
Thanks for the response and help everyone. I will take a close look and measure tonight to confirm. With the big price drop and availability news from p2m today, I'm pretty excited to get this ordered up.

Any thoughts on the bearing life of the original specialized bearings, per my comments above? Should I be ordering a new bb? And if I order a new bb/bearings, will the clips or cups (depending on what type I find I have) come as part of that new bb? If I don't need to order a new bb, can I just use the existing setup and install the rotor 3d+ straight away?


Top
 Profile  
 
PostPosted: Thu Sep 19, 2013 7:24 pm 
Offline

Joined: Thu Jan 21, 2010 4:18 pm
Posts: 84
Location: phoenix, az
Thanks to everyone that replied, I measured my bb shell width, and it is in fact the 61mm, making it the carbon osbb. It seems to be my understanding that the cups that then create the 68mm width are proprietary to Specialized, is that true? If so, then if one wanted to replace the bearings, they would simply order standard bb30 bearings and install them into the cups?


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 23 posts ] 
Go to page Previous  1, 2


Who is online

Users browsing this forum: Google [Bot], Google Adsense [Bot], lippythelion, sanddancer, tinozee and 50 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Specialized OSBB question

in Road

rOYk

2

564

Thu Nov 14, 2013 4:39 pm

weekapaugin View the latest post

There are no new unread posts for this topic. Specialized OSBB / Quarq

in Road

LoggingMiles

10

635

Sun Jan 26, 2014 1:14 am

LoggingMiles View the latest post

There are no new unread posts for this topic. How to install a BB30 crank on OSBB - cowboy style!

in Road

Elrey

0

588

Sat Dec 28, 2013 7:38 pm

Elrey View the latest post

There are no new unread posts for this topic. Rotor conversion BB with C'Dale crank?

in Road

FastforaSlowGuy

4

278

Tue Feb 18, 2014 7:56 pm

eric View the latest post

There are no new unread posts for this topic. Rotor 3D Mountain vs Road crank installation

in Road

Getter

3

338

Tue Mar 11, 2014 5:08 am

jooo View the latest post


It is currently Wed Sep 03, 2014 6:15 am

All times are UTC + 1 hour




Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by starbike.com


How to get rid of these ads? Just register!


Powered by phpBB