# Bottom bracket - metal thread insert loose in carbon shell?



## _Ed (Sep 2, 2009)

I noticed a little play in my bottom bracket a while back, but it wasn't getting any worse, so I wasn't too worried about it. 

This weekend I got round to getting the right tools, and sat down to strip down the BB and have a look what the problem was. I figured it was either a case of finding something loose somewhere, or the BB bearings being worn out and due for replacement.

The bike and BB (Ultegra 6600 English) are two years old, probably with around 20K km's on them.

Anyway, all looked good on inspection, so after cleaning I set about re-asembling everything. However, after getting everything torqued up as per shimano's guidelines, I noticed the play was still there.

At this point, I started assuming the bearings were worn hence the play, but on closer inspection I notice one of the outboard bearing holders moving up/down when the cranks were flexed, relative to the carbon bottom bracket shell - i.e. not the axel moving within the bearing.

As the bearing cups are definitely tightend up properly, and the play doesn't go even with lots of pre-load, I'm left thinking all it can be is the metal insert inside the carbon fibre BB shell must have come away from the CF shell on one side.

This is the first time I've dissasembles a road bike BB, so I'm hoping I've been a muppet and forgotton something obvious although I have a feeling I'm clutching at straws.

Any thoughts?


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## rx-79g (Sep 14, 2010)

How have you ruled out the play coming from inside the bearings themselves?

If the insert was loose, the BB would likely creak.


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## _Ed (Sep 2, 2009)

woah - speedy reply 

Well, mainly because I can see the outboard bearing moving relative to the carbon fibre shell.

when I re-inserted the bearing holder, I had applied lots of grease to the threads. When the holder was tightened up, a little of this grease ooze up in the gap between the CF shell and the metal holder.

i.e as you look at it you can see CF shell, 1mm band of grease, metal bearing holder.

When the cranks are flexed, you can see this grease moving .. i.e. the gap between the metal holder and CF shell getting smaller.

Hope that makes sense?

There is the occasional creak (although who knows where's it coming from) under hard standing pedalling, but nothing which would make you concerned.


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## rx-79g (Sep 14, 2010)

Okay, gotcha. Assuming the BB is installed and torqued correctly:

Aside from the thread insert being loose, it could some issue with a poorly faced BB shell (the frame), or something wrong with the external bb cup (cracked, warped or bad dimensions).

Either way, back to the dealer with it. It would be weird if it was a facing issue, but maybe the facing made the cup wear to a shape that can no longer be tightened properly. Or you could be right about the loose shell insert. But those are both defects in materials or workmanship = warranty.


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## frdfandc (Nov 27, 2007)

I just warrantied my bosses frame a few months ago for the aluminum BB shell separating from the carbon. 

Took a few pictures, sent them to the manufacture. New frame back arrived in 2 days.


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## PlatyPius (Feb 1, 2009)

Is it a Cervelo? They're famous for that.

Definitely sounds like the BB insert is floating free in the frame.


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## _Ed (Sep 2, 2009)

no, it's a Deda Nero Corsa (Ribble). I'll strip it down again this weekend and have a closer look at the BB insert, although I'm not sure I'll actually be able to see anything - it's probably less than a mm of movement at the BB (although that translates to a good bit of movement at the pedals), and when I was cleaning the BB insert, I didn't notice any moevement in there.


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## rx-79g (Sep 14, 2010)

_Ed said:


> no, it's a Deda Nero Corsa (Ribble). I'll strip it down again this weekend and have a closer look at the BB insert, although I'm not sure I'll actually be able to see anything - it's probably less than a mm of movement at the BB (although that translates to a good bit of movement at the pedals), and when I was cleaning the BB insert, I didn't notice any moevement in there.


Once you have the BB out, try sticking a large dowel or tool handle in the hole to leverage it around. You should be able to see the shell moving separate from the frame.


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## Chainstay (Mar 13, 2004)

How can the bearing holder be loose and wobbly? I would think it would easily break free of the BB and spin


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## _Ed (Sep 2, 2009)

Well, I stripped the cranks off again this weekend, to have a better look at the shell.

Just after I'd pulled the cranks, and played around with outboard bearings to see how they were moving, I noticed the little screw holding the cable guide on the BB shell was very loose. 

Without thinking, I tightened it up, and then went back to looking at the BB..... but all the play had gone!

Seem like that screw must go through the carbon outer and into the metal insert, and when it does that, everything tightens up..

Here's a little vid to demonstrate! You can the right hand bearing moving as I'm twisting the left hand side - as they're both screwed into the metal insert.

http://vimeo.com/19081009

Definitely not what I was expecting. I re-assmbled everything and now it's all working perfectly. Even the random creak I had has gone.


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## PlatyPius (Feb 1, 2009)

_Ed said:


> Well, I stripped the cranks off again this weekend, to have a better look at the shell.
> 
> Just after I'd pulled the cranks, and played around with outboard bearings to see how they were moving, I noticed the little screw holding the cable guide on the BB shell was very loose.
> 
> ...


There are NO carbon frames that use the BB cable guide screw to tighten up the BB shell insert; it's suppose to be glued/epoxied in. At some point, probably very soon, that screw is going to start moving back and forth again, and when it does, it's going to tear through the carbon on the bottom of the BB shell. At least this way it will be an even more obvious failure for the company to see....


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## -dustin (Jan 11, 2009)

that there was a perfect video. good job.

alu insert has debonded from the carbon shell. surprised it's not creaking.


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## _Ed (Sep 2, 2009)

yeah I figured the same. I didn't take the guide off to actually look at the hole in the carbon, so I'm not sure what state it's currently in. I would assume it would have already started to round out - I'm actually pretty suprised it tightened back up at all like it did.

Also, I'm not sure why it can spin so freely, but only through 15 degrees or so. I did back the screw completely out, but that isn't what's stopping it from going completely round.

Might be time to write an email to Ribble. They don't mention the warranty on frames on their site, so we'll see how far I get.

I've kind of been looking for an excuse to get a new frame anyhow!


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## _Ed (Sep 2, 2009)

Well, after speaking to Ribble, it looks like Deda have had a few of these frames go in the same way, and they are going to warranty it.

So, new frame should be on it's way soon!


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## l33boy (Jun 28, 2011)

_Ed said:


> Well, after speaking to Ribble, it looks like Deda have had a few of these frames go in the same way, and they are going to warranty it.
> 
> So, new frame should be on it's way soon!


Hi, sorry to drag this one up but I noticed exactly the same issue on my Ribble Nero Corsa this weekend. Did you manage to get your replacement? How old was your frame?
Like you I thought it was bearing play but nope... the whole insert can 'wiggle' about 1mm
This gives about 3mm movement at the top of the large chainring.... at the moment
Not Good!... Tightening the bolt makes no difference to mine either as it is more of 'wobble'.
Spoke to Ribble and they acknowledged the issue but said my frame was out of warranty!
Surely this is more of a manufacturing fault than a warranty issue ... No?
I've probably only done 2K with this frame over the last 2 1/2 years.


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## _Ed (Sep 2, 2009)

Yeah, I got the Nero RC as a replacement as they no longer make the Corsa. I contacted Ribble after 21months of owning the bike. I never found out what the actual frame warranty period was, but perhaps they agreed to replace mine as it was under 2 years? I'd probably done 15K km's on it by that point..

I guess the issue is how long Deda offer a warranty period on the frame for manufacturing defects, as that's definitely what it is.

Good luck in getting it sorted
Ed


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## l33boy (Jun 28, 2011)

_Ed said:


> Yeah, I got the Nero RC as a replacement as they no longer make the Corsa. I contacted Ribble after 21months of owning the bike. I never found out what the actual frame warranty period was, but perhaps they agreed to replace mine as it was under 2 years? I'd probably done 15K km's on it by that point..
> 
> I guess the issue is how long Deda offer a warranty period on the frame for manufacturing defects, as that's definitely what it is.
> 
> ...


Thanks for the response Ed, wow 15K in 21 months, obviously not just your race bike 

Just got another email from Ribble and they have agreed to replace the frame , 
Excellent stuff, hopefully the geometry hasn't changed much from the original Nero Corsa.
Thanks again


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## _Ed (Sep 2, 2009)

Good news!

The Nero Rc does have slightly different geometry to the Nero Corsa though, so you may want to take a look at the sizing charts in more detail.

Most significantly, the head tube on the RC is shorter. So if you're running the Nero Corsa with a lot of spacers, you may end up with a small spacer tower on the RC!

I use the bike for racing, training & commuting. I've got over 7K km's on the clock so far this year, so may get 15K in 12 months on the replacement frame


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## l33boy (Jun 28, 2011)

_Ed said:


> Good news!
> 
> The Nero Rc does have slightly different geometry to the Nero Corsa though, so you may want to take a look at the sizing charts in more detail.
> 
> ...


Cheers Ed, I'll check that now.
I do run my stem high for sportives and don't really want to cut my steerer any further.
The graphics may look a bit odd with my Easton forks but I'll live with it :thumbsup:
Thanks again buddy


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## birdadam (Apr 25, 2014)

Hi all,

Looking for some advice. I have a 2010 Felt F5 with this exact same issue - aluminum sleeve is delaminated from the carbon BB shell. There is some play in the cranks. I am working to get the frame warrantied (though not sure if I'll have any luck - I'm not the original owner). I'm wondering if it is safe to ride the bike while I'm sorting out getting a new frame. I can't imagine the cranks falling off, because everything is clamped together. my only concern is if the slightly wiggly aluminum sleeve will cause the carbon BB shell to crack and fail. Thoughts?

Thanks,

Adam


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## Jwiffle (Mar 18, 2005)

birdadam said:


> Hi all,
> 
> Looking for some advice. I have a 2010 Felt F5 with this exact same issue - aluminum sleeve is delaminated from the carbon BB shell. There is some play in the cranks. I am working to get the frame warrantied (though not sure if I'll have any luck - I'm not the original owner). I'm wondering if it is safe to ride the bike while I'm sorting out getting a new frame. I can't imagine the cranks falling off, because everything is clamped together. my only concern is if the slightly wiggly aluminum sleeve will cause the carbon BB shell to crack and fail. Thoughts?
> 
> ...


I don't think the bb will suddenly catastrophically fail. If you can live with the play, it's probably safe enough.


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## birdadam (Apr 25, 2014)

Thanks for the input. That was my intuition as well.

Has anyone ever heard of a carbon frame failing (carbon cracking, slowly or catastrophically) due to a loose BB sleeve?


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## bikerjulio (Jan 19, 2010)

I have a BMC frame that was an eBay purchase and obviously well-used. 

After a while noticed this exact problem. The insert was anchored securely at the middle of the BB but there was noticeable play on both sides.

Although I was criticized at the time for my method of dealing with the problem, it's held up just fine for a couple of years now.


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