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PostPosted: Wed Aug 03, 2011 2:21 pm 
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Joined: Tue Mar 20, 2007 5:56 pm
Posts: 980
So I just got one of these, new, and installed on my bike.
Now, I know that spinning the cranks in the workstand doesn't mean a whole lot.
But I found it odd that when spinning the cranks on my newly installed SRAM GXP ceramic BB, they have more resistance than a typical shimano BB.
In fact, the non-ceramic SRAM truvativ BB cups I've used in the past spin with a lot less resistance than this ceramic version.

Do they purposely use tighter seals on the ceramic version??


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PostPosted: Wed Aug 03, 2011 3:50 pm 
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Joined: Fri Mar 18, 2005 4:12 pm
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Location: eh?
That's not what you want to find out when you go for the high end BB. Assuming proper installation, hopefully it will free up with some use.

I do want to put in a good word for the SRAM press fit BB that I have just installed. It is absolutely free spinning from the first turn of the pedals. Much superior the the Shimano press fit it replaced. When I first tested the bike it felt super smooth in my feet and I assumed it was the new cranks or just in my head. However on the workstand later without the chain, I could confirm that indeed this was an excellent part.

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Mr.Gib got it right


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Posted: Wed Aug 03, 2011 3:50 pm 


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PostPosted: Wed Aug 03, 2011 6:46 pm 
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Joined: Thu Sep 30, 2010 5:50 am
Posts: 315
My experieince with SRAM PF30 is that on initial installation it was not that free spinning but after 50 miles or so it spins nicely with chain off.

I would say give it some miles and it will probably spin well.


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PostPosted: Wed Aug 03, 2011 8:16 pm 
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Joined: Fri Apr 18, 2008 12:55 am
Posts: 129
Bearings have a break in period. Some wheels take a couple hundred miles to get spinning smoothly and the same can be said for bb bearings. Give it a couple of weeks and it should be good!


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PostPosted: Wed Aug 03, 2011 9:26 pm 
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Joined: Wed Jan 26, 2011 3:14 pm
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I think in SRAM's tech videos on youtube they tell you to expect a break-in period.


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PostPosted: Thu Aug 04, 2011 4:21 am 
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Joined: Sat Jun 13, 2009 4:02 am
Posts: 1951
Location: NoVA/DC
hopefully you got the new version with the GutterSeals n such. their seals have much less drag than their old ones.


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PostPosted: Thu Aug 04, 2011 12:49 pm 
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How would I tell if it had the new seals on it? I still have the original box it came in, would there be something specific marked on it?
Thx


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PostPosted: Thu Aug 04, 2011 7:14 pm 
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Joined: Sat Jun 13, 2009 4:02 am
Posts: 1951
Location: NoVA/DC
the new ceramic bottom brackets have red cups.
Attachment:
gxp ceramic 2011.jpg
gxp ceramic 2011.jpg [ 52.79 KiB | Viewed 411 times ]


the old ones had polished silver cups that are a bit more square-edged
Attachment:
gxp ceramic 2009.jpg
gxp ceramic 2009.jpg [ 51.66 KiB | Viewed 411 times ]


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PostPosted: Thu Aug 04, 2011 7:22 pm 
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I gots the old... :(


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PostPosted: Sat Aug 06, 2011 1:50 pm 
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Joined: Sat Apr 09, 2011 11:29 pm
Posts: 767
Location: Springdale, AR
I gots the new... :D

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PostPosted: Sat Aug 06, 2011 1:54 pm 
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Joined: Sat Apr 09, 2011 11:29 pm
Posts: 767
Location: Springdale, AR
addicted wrote:
So I just got one of these, new, and installed on my bike.
Now, I know that spinning the cranks in the workstand doesn't mean a whole lot.
But I found it odd that when spinning the cranks on my newly installed SRAM GXP ceramic BB, they have more resistance than a typical shimano BB.
In fact, the non-ceramic SRAM truvativ BB cups I've used in the past spin with a lot less resistance than this ceramic version.

Do they purposely use tighter seals on the ceramic version??


I believe it's the seals on the SRAM GXP BBs. They are tighter to begin with, but break in quickly. Just give it a week or two...then recheck it.

_________________
Specialized Allez 06' "Rain Bike" 21.50lbs
Neuvation F100 11' "Road Bike" 16.80lbs
Specialized Tarmac Pro 11' "WW Bike" 14.25lbs


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PostPosted: Sat Aug 06, 2011 2:52 pm 
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Joined: Fri Feb 08, 2008 11:37 pm
Posts: 24
Never been a fan of ceramic bearings. I've had several fail within 1000 miles where standard steel balls (sounds painful) are still going strong.


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Posted: Sat Aug 06, 2011 2:52 pm 


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