Bottom Bracket creak

nevica

Hello,

I have a carbon frame and I also have a creak from the bottom bracket which tends to be slight and intermittent. The creak isn't necessarily from the bottom bracket it only emanates from there). I'd like to try and locate what the source of the creak is.

The bike has seen two mechanics and here is what I have done to locate the creak.

1. Bottom bracket removed, regreased and re-assembled.
2. Chunkier Campagnolo skewers installed in front and back wheels. This removed a lot of the creak but there is still an intermittent one which I think is emanating from somewhere other than the skewars).
3. Bottle holder tightened. ( I know its not the bottle holder.)
4. Creak happens in or out of the saddle so its not the seat post.
5. Its not from the handlebars.
6. Changed peddles to different types multiple times.
7. Tightened the peddle cleats in the shoes.

At present the creak only occurs on the flat when pedaling under moderate power and when going downhill pedaling. For some strange reason it does not occur when going uphill! I suspect the culprit is the pedals or cleats but having changes the pedals and cleats multiple times this has left me stumped as to what the culprit is.

Any ideas please?

Thanks,

Daniel

mitchgixer6

Chainring bolts re greased and re fitted?

sungod

creaks etc. resonate through the frame, so localising can be hard

one thing to try...

hold the head tube with one hand, arm outstretched, and the seatpost with another, close to shoulder with arm bent, push/pull hard on post, see if there's a click/creak due to the post shifting a nanosmidge

Matthewfalle

Has it been out in the rain? Weave weft probably.

Can you post pictures of any visible lay up in the areas you think the noise is emanating from so we can see?

nevica

I'm sorry, I don't quite understand why you want to see photographs. What do you mean by lay up? No I don't ride my carbon bike when it rains.

lapavoni10

You mention Campag...if its an ultra-torque BB, I had same issue with the wavy washer and the bearing on that side.
Make sure the wavy washer is completely clean, plenty of grease, and also grease the cups.
I am not 100% sure if these should be dry fit, but mine creak like mad if they are dry.

Other thing to check is if you have slightly too much steerer and its creaking against the top cap.

nevica

No, I have a Truvativ BB30 bottom bracket. I have Campagnolo skewers in the wheels which are sturdy skewers and hold the wheels really well.

I took the chainring bolts off last night and found that one bolt out of five was very weak. It snapped as I was putting light allen key pressure on it. I find that Truvativ chain ring bolts are not very strong so I am going to purchase some Titanium bolts which I hope fix the problem.

DeVlaeminck

Matthewfalle wrote:

Has it been out in the rain? Weave weft probably.

Can you post pictures of any visible lay up in the areas you think the noise is emanating from so we can see?

Little tip, spray your bike monthly with that shoe protector spray you can get from any shoe shop, or after cleaning with any kind of cleaning product, I haven't lost a carbon frame due to rain since I started doing it 4-5 years ago.

Old_Timer

Since its a BB30 bottom bracket I'd tend to suspect that you need to use the green Loctite and do the rework again. Pull everything out, clean thoroughly and then reassemble with good waterproof grease (I use Belray blue waterproof marine grade) and apply the Loctite to the bearing cartridges and bracket face where the bearing sits. Be sure it is installed squarely and fully seated. There is a tech bulletin on the Cannondale website about doing the BB30 refit for creaks and popping that gives you the specific Loctite product that is recommended. http://www.cannondale.com/manual_accessories/ This is the folder, click on the BB30 section for the PDF file.

nevica

Hello Old_timer,

You don't give a reason that you think it is the bottom bracket.

Did you read my first post right to the end? The creak doesn't happen when I am pedaling up hill, only on the flat and down-hill. I find this very unusual. Do you still think it is the BB.

topdude

4. Creak happens in or out of the saddle so its not the seat post.

This is a common mis-conception, the frame / seatpost still flexes whether riding seated or standing :?

You need to strip / clean / grease (assembly compound) all contacting parts of the seatpost / clamp & seat tube.

Matthewfalle

DeVlaeminck wrote:

Matthewfalle wrote:

Has it been out in the rain? Weave weft probably.

Can you post pictures of any visible lay up in the areas you think the noise is emanating from so we can see?

Little tip, spray your bike monthly with that shoe protector spray you can get from any shoe shop, or after cleaning with any kind of cleaning product, I haven't lost a carbon frame due to rain since I started doing it 4-5 years ago.

Agree completely - very, very good tip. I do this quite a lot and have also not lost a frame for ages.

It's also worth taking the seat post out and spraying a good amount into the frame as well to make sure that any water that gets in there doesn't cause an infarction of the lay up.

The lay up is the actual carbon sheeting that is glued together to make the frame - if you post a picture we can see if there is any weft or infarction that may be causing the creak.

nevica

Hello,

The carbon fibre is completely painted over and I don't see any loose wefts of carbon around the bottom bracket area. Its a practically new frame.

As regards the shoe polish stuff you will have to convince me that using this is beneficial. I certainly don't want to walk into a shoe shop and ask for 'shoe protector spray that protects carbon bike frames'. I will look rather silly. Forgive my irony but you will have to be more specific as to what you mean?

mitchgixer6

Don't rise to it mate.

These 2 idiots seem to think it's funny to try and wind someone up who has a genuine issue. Please keep the sarcasm and jokes to the appropriate section of the forum guys.

Crozza

my bet is the chainring bolts - in my case I had one that wasn't quite snug. I took the crankset apart and greased where the chainrings joind, and where spider joined, greased bolts and put it all together super tight

creaking was horrendous before that (one stranger offered to buy me a new bottom bracket ) but this fixed it

Matthewfalle

mitchgixer6 wrote:

Don't rise to it mate.

These 2 idiots seem to think it's funny to try and wind someone up who has a genuine issue. Please keep the sarcasm and jokes to the appropriate section of the forum guys.

Due to a former career, I'm actually a past advisor on material kinetics and wear to the MOD and French government - I advised on the use of Kevlar, carbon and Chobham during and following Ops Tosca, Herrick and Telik.

I also worked for Lord Bach when he was Minister of Procurement when the guys at QinetiQ were developing a few bits so have a fair idea of how weather, stresses and use affect material composites such as carbon fibre. An open mould bicycle isn't really up to the same standards as the bits I was advising on, so I'm fairly confident in what I'm talking about.

Carbon fibre matting is, essentially, just strands of carbon fibre laid out either lengthways or sideways dependant on usage - its then covered in glue, taken to the mould etc. The glue is porous.

The paint used on them is water based as sprayers don't like getting cancer from 2 Pac and you can't powder coat carbon - its also porous.

The holes in your frame (headset, b/b, cables, brakes, etc) also allow water into the frame - this is why sometime after a good wash and clean when you stand it on end water comes out.

The shoe covering is a good idea - its light, non toxic, non abrasive and provides a nice finish to the frame (non matting) while filling in the microscopic holes that cause the porous effect. Its also cheap.

Doing the outside is very, very good advice and a given (prevents weft, or the twisting and changing of direction of laid up fibres due to moisture, commonly found on high level racing yachts), but the inside covering will prevent infarction (basically the same but a material composite form of filiform that affects aluminium).

Bizarrely, the suede stuff works best due to its design to stop water affecting suede which is the hardest leather to keep dry - normal leather shoes can just use polish.

Your local Clarks or old person's shop will do the biggest and cheapest cans as generally old people use it more.

Its just a tip but it works for me and dude above - but hey, ts your bike and money. I haven't had a frame weft/infarct on me for a good few years and I know a load of the World tri/ironman guys also use.

HTH

M

Crozza

it's the first time I've ever heard of this. doesn't the clear coat effectively "seal" the carbon fibre anyway?

Crozza

ps - what is an "old person's shop"?

Old_Timer

nevica wrote:

Hello Old_timer,

You don't give a reason that you think it is the bottom bracket.

Did you read my first post right to the end? The creak doesn't happen when I am pedaling up hill, only on the flat and down-hill. I find this very unusual. Do you still think it is the BB.

Yep, I read your entire post, and its strictly a guess based on the numbers of BB30 owners reporting problems like yours. The fact it is not creaking while pedaling up hill isn't a total reason for ruling out the BB, that could be a case of your putting more weight on to the BB spindle holding things down until you are seated. Creaks and noises can be frustrating, as said the frame can transmit the noise away from the source and fool us as to what is wrong. I just wanted to offer a thing to look at and read the link, if it isn't helpful, my apologies.

As to the replies so far I think Matthewfalle has the best and his information seems to be solid to me. My background is materials failure analysis for structural steel building members and fasteners (bolts for connections) and in concrete failure analysis.

nevica

Hello Old-Timer,

Ok, thanks for advice. I am going to check my seat post and seat clamps.

Just to re-iterate though:

When I am pedaling uphill I DON'T hear the creaking noise. When I am pedalling on the flat or downhill I hear an intermittent creak from the bottom bracket.

Daniel

mitchgixer6

Matthewfalle wrote:

mitchgixer6 wrote:

Don't rise to it mate.

These 2 idiots seem to think it's funny to try and wind someone up who has a genuine issue. Please keep the sarcasm and jokes to the appropriate section of the forum guys.

Due to a former career, I'm actually a past advisor on material kinetics and wear to the MOD and French government - I advised on the use of Kevlar, carbon and Chobham during and following Ops Tosca, Herrick and Telik.

I also worked for Lord Bach when he was Minister of Procurement when the guys at QinetiQ were developing a few bits so have a fair idea of how weather, stresses and use affect material composites such as carbon fibre. An open mould bicycle isn't really up to the same standards as the bits I was advising on, so I'm fairly confident in what I'm talking about.

Carbon fibre matting is, essentially, just strands of carbon fibre laid out either lengthways or sideways dependant on usage - its then covered in glue, taken to the mould etc. The glue is porous.

The paint used on them is water based as sprayers don't like getting cancer from 2 Pac and you can't powder coat carbon - its also porous.

The holes in your frame (headset, b/b, cables, brakes, etc) also allow water into the frame - this is why sometime after a good wash and clean when you stand it on end water comes out.

The shoe covering is a good idea - its light, non toxic, non abrasive and provides a nice finish to the frame (non matting) while filling in the microscopic holes that cause the porous effect. Its also cheap.

Doing the outside is very, very good advice and a given (prevents weft, or the twisting and changing of direction of laid up fibres due to moisture, commonly found on high level racing yachts), but the inside covering will prevent infarction (basically the same but a material composite form of filiform that affects aluminium).

Bizarrely, the suede stuff works best due to its design to stop water affecting suede which is the hardest leather to keep dry - normal leather shoes can just use polish.

Your local Clarks or old person's shop will do the biggest and cheapest cans as generally old people use it more.

Its just a tip but it works for me and dude above - but hey, ts your bike and money. I haven't had a frame weft/infarct on me for a good few years and I know a load of the World tri/ironman guys also use.

HTH

M

Ah, so it seems carbon fibre DOES melt in the rain after all.

nevica

I don't ride my carbon bike in the rain + its practically a new bike so I can rule out water ingress at this stage.

Thanks for you advice on the shoe polish.

nevica

So, just to clarify.

You advise spraying inside of the frame with a shoe polish product.

You also advise spraying the outside of the frame as well because the paints and lacquers used on carbon bikes are porous.

This raises questions.

1. What parts of the frame are to be avoided (both inside and out).
2. How much should one use?
2. Shoe shops sell many products. Can you give me a specific product to use?

Matthewfalle

nevica wrote:

I don't ride my carbon bike in the rain + its practically a new bike so I can rule out water ingress at this stage.

Thanks for you advice on the shoe polish.

No problem - glad to be of help. Remember it's not polish though but the suede protector spray.

Ref clear coat: it's a semi permeable - it does a great job but again will allow water ingress. You'll see a slightly different finish on military carbon parts (wings, radar covers, etc) for both physical and weather defensive reasons.

Moonbiker

My LBS doesn't stock carbon fibre bikes due to it being Wales & the higer annual rainfall & humidity than other parts of the UK causing issues with delamination or "melting".

Matthewfalle

Strangely enough, we refused to issue some special kit to people who were intent on using it on Brecon due to the same reason. Obviously one group of guys we didn't mind, but generally it was a no - no.

It was the same in the rainy season in Somailia when we were out there (previous French work) - the humidity and inherent dampness caused masses of issues with pure carbon based materials - bi-material and tri-complex materials were fine but pure carbon fibre caused a massive headache.

Development of meta materials partially solved this but I understand that QinetiQ are still trying to workout a solution - essentially its all to do with synthetic, semicrystalline organics. And if they can't do it, I can fully understand why the average bicycle manufacturer is still having issues.

tuneskyline

Try a different back wheel and see what happens. A lot of creaking from the back of the bike does sound like it's coming from the bb area. Could be you just need to lube your rear wheel.

me-109

nevica wrote:

When I am pedaling uphill I DON'T hear the creaking noise.

That's because the blood pounding in your head drowns it out.

Old_Timer

Nevica,
Had any luck chasing down the noise?

nevica

I took the back wheel off last night and inspected the axle. I noticed a loose tightening ring holding the bearings. Took off the cogs and tightened this ring.

I have also removed and re-installed my chainring bolts having found one bolt which was a bit weak (it broke when I re-installed it). Secondly, I have used a little carbon grease on my seat post and holding assembly.

As yet I have not had chance to test the bike but will report back with: a yes (it's fixed) or a no (its not fixed) in due course.

Thanks,

Daniel