Carbone steerer damaged ?

TeamLaVaylie

Hi,

After my first test ride and a check of my bike, headset am so on, I noticed this mark about 1cm on the top of the steerer tube, at the stem level.
Is that damaged or safe to keep riding with that ?
I wonder if the carbon quality is not involved in that change and suspect the stem pressure might have caused it.
I am thinking to go to the LBS to make sure it is safe. No marks or cracks further below.

https://www.flickr.com/photos/149539448 ... res/68J37A

Thanks for your advice.

John

sigorman85

That sir is a cracked steering tube back to the shop it goes and the answer is I haven't tightened anything on the bike and if I did I would use the correct torque settings or bring it to the shop to do ...

noodleman

Looks a bit like a manufacturing defect. Taking the stem off is a strange thing to do after a test ride though :?

jermas

Definitely cracked- don't ride! Did the steerer have a bung installed? If not, that probably caused the problem.

TeamLaVaylie

Thanks for your replies and advices, guys.
I did the built-in by myself, but as far as I know, did respect the procedure and used a torque wrench.
Wanted to add some grease to the bearings headset after the first ride, that’s why I had a look at it.

imposter2.0

You wanted to grease the headset after your first ride on a brand new bike? What bike is it as a matter of interest?

vinnymarsden

Can I ask...what torque setting you used?? and what fork is it??
If you went the correct stem setting of 5-7nm that should NEVER happen..unless it is inferior carbon...Chinese frame etc...not saying it is, or that they are all bad...but that should not happen at correct settings etc

jermas

If you went the correct stem setting of 5-7nm that should NEVER happen

Unless a bung wasn't fitted.

cougie

My money is on installation error there.

TeamLaVaylie

Used 4nm on my torque wrench for the stem tightening
Super six evo no spacer above the stem as per cannondale manual

imposter2.0

TeamLaVaylie wrote:

Used 4nm on my torque wrench for the stem tightening
Super six evo no spacer above the stem as per cannondale manual

Was the bung inside the steerer when it cracked? If it was installed, I can't really see how it could have happened.

TeamLaVaylie

yes. the bung was inside
the lbs told me today that by putting epoxy and the stem lower it should be fine but the fork will be sent for checking to the maker

mamba80

TeamLaVaylie wrote:

Used 4nm on my torque wrench for the stem tightening
Super six evo no spacer above the stem as per cannondale manual

any bike i ve built or owned has always had the stem fully clamped on the steerer and that requires a 5mm spacer above, means that the stem clamps fully onto the part of the steerer in-line with the bung.

Anyone like to guess what Canondale will say?????

killabeezz

Then possibly the 'bung' was in the wrong position? if you dropped the stem it would be too high ( it should be at the same depth in the carbon steerer as the stem clamping bolts)
The bung stops crush loads from the stem when this is tightened

keef66

mamba80 wrote:

TeamLaVaylie wrote:

Used 4nm on my torque wrench for the stem tightening
Super six evo no spacer above the stem as per cannondale manual

any bike i ve built or owned has always had the stem fully clamped on the steerer and that requires a 5mm spacer above, means that the stem clamps fully onto the part of the steerer in-line with the bung.

Anyone like to guess what Canondale will say?????

When I assembled my Scott CR1-SL their advice was no spacers above the stem. The suppled bung sits slightly proud of the top of the steerer so it would be pretty difficult to produce the kind of damage you've got.

Other manufacturers use a bung that can be fitted lower down in the steerer, and then specify a spacer above the stem to prevent the steerer tube being clamped right at the top where it's unsupported and weakest.

jgsi

Key thing is - do not over tighten those stem bolts.

jermas

Did you torque the stem bolts in increments? It's possible the damage occurred by tightening the top bolt fully, then the bottom fully -rather than in stages between the two.

svetty

Does look like over-tightening of top stem clamp bolt - suggesting either installation error or manufacturing defect - which I would suggest is possible but unlikely. The marks on the inside of the tube do suggest that the bung was correctly inserted as far as I can see........
Assuming no warranty replacement your best bet is to shorten the steerer by cutting below the crack, then using a stem inverted to 'add back' the lost height. And make sure the bung is correctly placed when refitting the stem using a calibrated torque wrench.

on-yer-bike

Is there any reason other than aesthetics to not put spacers above the stem? It means you are only left with downward adjustment and non if you've slammed your slammed

trailflow

TeamLaVaylie wrote:

yes. the bung was inside
the lbs told me today that by putting epoxy and the stem lower it should be fine but the fork will be sent for checking to the maker

f**k*ng epoxy LOL ? What a bunch of jokesters. What if it wasn't fine though? and the steerer snaps clean off while your descending at 30+ mph and you loose all ability to steer and crash. And that results in your death (god forbid). Im sure they will take full responsibility of recommending you to 'risk' it because they thought so. They cant possibly know it will be fine by just looking at it. They're guess is a good as yours, anybody elses. The steerer is the most safety critical part on the bike. It's not something you just take a chance on. Especially when there is a clear crack like there is here. The damage to the carbon could extend further down inside thats not visible to the outside. Bike shops/mechanics are not safety specialists or composite engineers (but some seem to think they are). So please dont take their advice here. It's bogus.

No way will Cannondale give the OK to ride that. It's terminal. I hope they just fast line the return process and replace it out of good will to get you on the road and riding.

It's an unfortunate thing to happen with a brand new bike. Whether it was user mistake or a manufacturing mistake only you can know. But it can be replaced. Your life cannot. For the love of god. Do not ride that steerer.

On to the installation of the stem. The only thing thats bugs me about using torque wrenches is, they may not be calibrated correctly. So i choose not to use them. And countless other people choose not to use them too. In all honesty bike bolts do not need to be done up very tight at all. They just need nipping up,not clamping down to the maximum so to speak. Ask a different bike shop to show you how to do it if in doubt. And with stem/handlebar bolts. Incrementally in very small movements and alternating as suggested above is the best way to do it, to even spread the load force. Then periodically check each and re-tighten each bolt a smidgen if they have loosened at all from riding.

onionmk

Don't ride it! Get in touch with the manufacturer ASAP and hope to get it replaced. It might cost you, in which case you'll need to decide whether it's worth it ( considering the cost of the bike). I'd rather that than a broken collar bone or worse.

on-yer-bike

If the bung has made that impression in the tube then it must have been done up pretty tight.

Lookyhere

trailflow wrote:

TeamLaVaylie wrote:

yes. the bung was inside
the lbs told me today that by putting epoxy and the stem lower it should be fine but the fork will be sent for checking to the maker

f**k*ng epoxy LOL ? What a bunch of jokesters. What if it wasn't fine though? and the steerer snaps clean off while your descending at 30+ mph and you loose all ability to steer and crash. And that results in your death (god forbid). Im sure they will take full responsibility of recommending you to 'risk' it because they thought so. They cant possibly know it will be fine by just looking at it. They're guess is a good as yours, anybody elses. The steerer is the most safety critical part on the bike. It's not something you just take a chance on. Especially when there is a clear crack like there is here. The damage to the carbon could extend further down inside thats not visible to the outside. Bike shops/mechanics are not safety specialists or composite engineers (but some seem to think they are). So please dont take their advice here. It's bogus.

No way will Cannondale give the OK to ride that. It's terminal. I hope they just fast line the return process and replace it out of good will to get you on the road and riding.

It's an unfortunate thing to happen with a brand new bike. Whether it was user mistake or a manufacturing mistake only you can know. But it can be replaced. Your life cannot. For the love of god. Do not ride that steerer.

On to the installation of the stem. The only thing thats bugs me about using torque wrenches is, they may not be calibrated correctly. So i choose not to use them. And countless other people choose not to use them too. In all honesty bike bolts do not need to be done up very tight at all. They just need nipping up,not clamping down to the maximum so to speak. Ask a different bike shop to show you how to do it if in doubt. And with stem/handlebar bolts. Incrementally in very small movements and alternating as suggested above is the best way to do it, to even spread the load force. Then periodically check each and re-tighten each bolt a smidgen if they have loosened at all from riding.

Yes say £400 (perhaps a week or two wages) for a new painted fork V severe gravel rash, broken wrist, collar/shoulder bone, facial fractures and dental bill?

plus wrecked helmet, bike and wheels.

No brainer really.

fwiw i had exactly the same dilemma with a 2nd hand 585, very very faint crush marks on steerer, LOOK sold me a new fork, its never worth it.

Monty Dog

Crush-damage by the look of it and it's highly improbable than Cannondale would say it's safe to ride. Doubt there's any case for warranty, but they might do a deal on a crash-replacement?

Rightarmbad

Who greases new headsets on bikes?
Every good shop takes it apart and puts it back together again using grease and carbon paste where required.
That stem was too high on the steerer, there is no way it was within the normal overhang for a steerer.
Somebody has put an extra spacer under the stem that should not have been there. You needed the next frame size up or an upward facing stem installation.
No decent shop would have set that up like that and if they did it is their responsibility to fix it.
The markings for bolt torques are maximums not recomended.
Use friction paste and do up to required amount to stop it moving and make sure stem gap is consistent, not tapered.

keef66

on-yer-bike wrote:

Is there any reason other than aesthetics to not put spacers above the stem? It means you are only left with downward adjustment and non if you've slammed your slammed

It's less about aesthetics and more about safety (and in the USA, fear of litigation)

With a bung that sits flush with or slightly proud of the top of the steerer like mine, fitting spacers above the stem could mean that the lower part of the stem is clamping the steerer below the part supported by the bung, potentially crushing it or failing to clamp it securely. Neither of those is a good thing...

The alternative would be to replace such a bung with one you can install at any depth in the steerer, and ensure you place it exactly where it's required to support the steerer against the stem clamp.

Mind you, having tried to crush the offcut from my carbon steerer I can say the stuff is pretty robust. I think you'd really have to try hard to do what the pic suggests happened unless the thing had some kind of defect to start with, or the torque wrench was faulty.