Cracked frame or cracked paint? Help please

[avecReynolds531]

I'd be grateful for the views of the CC people who know about this please.

I've had this road bike for over 14 years - the bb is stamped 09/00 which could be September 2000. Over the last year cracks have appeared around the headtube lug - around the top and down both sides, bottom bracket/ seat tube area (both sides), and now starting at the top of the seat tube area.

These are aluminium lugs - bonded with carbon main tubes. The frame doesn't feel at all different when riding, and isn't making any creaks or noises.

It has been stored in a colder room the last few years.

An excellent LBS checked it last week, but after that journey which added up to a 25 mile loop, the cracks seem to have increased in length. It's not just visual - you can feel the difference across the line.

Apologies for the quality of the photos - I found it difficult to get the problem shown clearly.

Head tube - jagged (shark tooth) lines curving round clockwise

BB area- a dark line that looks like a smile

3. Left side of head tube - curving round anti clockwise with the start of a branch line heading south west

4. Again the curve anti clockwise. This crack travels all the way around the top of the head tube linking the other side.


Is it a terminal fault in the aluminium or hopefully something to do with the paint lacquer?

It's easy to be attached to a frame - especially when you've had it many years, it rides beautifully and you have memories of some of the great climbs of the Alps & numerous other brilliant days out...
but... if it's due a catastrophic failure then I'll happily retire it.

There's an interesting link here detailing the Pinarello/ Opera story which includes a post about a lot of broken frames: https://weightweenies.starbike.com/forum/viewtopic.php?t=23043&start=0

Any and all advice & views are much appreciated.

Thanks,

Tom.

 

[fossyant]

Hmm, I don't like the look of the head tube.

 

[avecReynolds531]

Hmm, I don't like the look of the head tube.

Thanks for the reply - what is it about the head tube that causes concern?

More generally, is this common for bonded frames?

Is it rare for lacquer to crack & possibly cause an effect like this?

 

[MntnMan62]

You said your LBS checked it out last week. What did they say about all of this?

 

[classic33]

If that were mine, I'd be bothered about the line on the seat tube/bottom bracket joint. Normally I'd say it's possible that the weld is giving, along the line of the actual joint.

You appear to have another "crack" on the rear of the bracket. Again where tubes meet.

 

[Johnsco]

It looks to me to be potentially serious.
Aluminium welding is not the easiest technology.
Aluminium to carbon even less-so.
The definitive test for cracks in these materials is a dye-penetrant non-destructive test (NDT).
It's a cheap and cheerful test, but it may require the removal of an area of paint in the area to be tested.
When you remove the paint, the answer may be evident anyway and you may quickly see that it is cracked.
The dye-pen test depends on applying a penetrating red dye to the suspect area.
The dye will soak into any cracks by capillary action.
You let it soak for about 10 minutes, wipe off any excess dye.
Then after a short wait, you spray the area with a white powder coating.
Any dye in the crack will bleed out into the white coating and this will confirm a crack.
You can cheat and use oil mixed with paraffin as your dye.
Wipe it off and then dust the area with fine flour or talcum powder.
The oil should bleed out and trace out any cracks.
Shame about your paint finish .... It looks great.

Johnsco
(Retired NDT Engineer)

 

[midlife]

Aluminium lugs with bonded carbon tubes..... I was expecting something like an Alan carbonio

https://lfgss.microco.sm/api/v1/files/c9ed7853cd83c7d08879eeb792827599f2b80162.jpg

 

[avecReynolds531]

You said your LBS checked it out last week. What did they say about all of this?

They thought it's movement of the joints - carbon & aluminium - in the bonded frame. With it riding no differently and not making any creaks/ noises, keep an eye on it for worsening. When I got home, the cracks seemed to have increased even after that ride!

If that were mine, I'd be bothered about the line on the seat tube/bottom bracket joint. Normally I'd say it's possible that the weld is giving, along the line of the actual joint.

You appear to have another "crack" on the rear of the bracket. Again where tubes meet.

Thanks for that. From the attached Weight Weenies article: 'When Team Fakta rode the Opera Giorgione, they broke a huge amount of them. I have personally seen four or five that were broken at the BB/chainstay junction. '

It looks to me to be potentially serious.
Aluminium welding is not the easiest technology.
Aluminium to carbon even less-so.
The definitive test for cracks in these materials is a dye-penetrant non-destructive test (NDT).
It's a cheap and cheerful test, but it may require the removal of an area of paint in the area to be tested.
When you remove the paint, the answer may be evident anyway and you may quickly see that it is cracked.
The dye-pen test depends on applying a penetrating red dye to the suspect area.
The dye will soak into any cracks by capillary action.
You let it soak for about 10 minutes, wipe off any excess dye.
Then after a short wait, you spray the area with a white powder coating.
Any dye in the crack will bleed out into the white coating and this will confirm a crack.
You can cheat and use oil mixed with paraffin as your dye.
Wipe it off and then dust the area with fine flour or talcum powder.
The oil should bleed out and trace out any cracks.
Shame about your paint finish .... It looks great.

Johnsco
(Retired NDT Engineer)

Thanks, that's really helpful information & much appreciated.

Aluminium lugs with bonded carbon tubes..... I was expecting something like an Alan carbonio

https://lfgss.microco.sm/api/v1/files/c9ed7853cd83c7d08879eeb792827599f2b80162.jpg

Thanks, I knew Alan (nice frame!), Vitus, Trek, Specialized and Giant have tried the bonded alu/ carbon method.

Here's the bike - the dark blue painted areas are carbon, the lighter blue aluminium. Pinarello didn't make this one for long - it was superceded quickly. Maybe I know why now.

Thanks for all the input & advice - I'm getting to the point where I don't want to risk it anymore. As I'm getting older & less flexible, the riding postion has been more uncomfortable in any case, so it's most likely best to call it a day.

 

[byegad]

Looks serious. Short of x-raying the frame, scraping the paint off in the affected area will show how deep the crack goes.

 

[rogerzilla]

Can you have someone flex it by standing on one pedal with the front brake locked, while you look at the BB crack?

 

[Johnsco]

QUOTE: Short of x-raying the frame, scraping the paint off in the affected area will show how deep the crack goes

X-raying is a quite expensive nondestructive test, and the bike needs to be taken to a specialist X-ray bay to be X-rayed.
The dye penetrant test is a cheap and cheerful test and will detect any surface-breaking crack in aluminium welded joints.

 

[avecReynolds531]

Thanks for the further knowledge shared & advice - much appreciated.

Thinking along the lines of whether I scrap the frame, put in on the wall inside a picture frame (& sit in relaxation, remembering many fine bike rides), or donate it to someone who could have some use for it.

An associated CC thread regarding carbon / aluminium has this post & a photo
from Globalti: 'No, you get cracks in the very thick brittle paint where the joint flexes.'
https://www.cyclechat.net/threads/carbon-frame-corrosion.185290/page-2

...which seems to be along the same lines of what the LBS were saying? If there's the possibility that it is only the paint, then it changes the idea of scrapping the frame.

I like the relative simplicity of a steel frame!

 

[MntnMan62]

I too have an aluminum and carbon frame. Motobecane Sprintour from Bikesdirect.com. The only parts of mine that are carbon are the fork and the rear seat stays. And the joints are not painted over. The carbon is exposed and the painted aluminum stops abruptly so the joints are visible. But this thread has at least made me aware that this is something that could occur sometime in the future with my bike and I need to keep an eye out.

As for the OP’s bike it seems that if the problem was only minor the cracks in the paint would only be occurring at one joint. But with the cracks appearing in several locations it suggests a pretty major structural defect that has the potential for a catastrophic failure at any point during a ride. If it were my bike and I had been able to get 15 or so years of great rides from it, I’d hang it on the wall and move on. But it’s important to note that I am not a structural engineer. Far from it. I’m watching this thread to see what the ultimate outcome is.

 

[Johnsco]

As the world health guy said ...
" TEST - TEST - TEST "

 

[wafter]

Tbh I'm having a job getting my head around the actual construction of the frame; from the description I was expecting a more traditional steel frame type construction, with male CFRP tubes bonded inside female ally lugs; yielding a clear diameter change at the demarcation point between the two.

As it stands this example looks more like either a mixture of ally and CFRP tubes all bonded together as you'd weld similar metals (joints I suspect would be extremely weak) or maybe ally "lugs" (fabricated with smoothed welds?) that have reduced diameter female bosses that are then bonded into the ID of the CFRP tube, and smoothed to give a seamless transition..?

In a more simple sense, is it safe to assume that all of the areas where cracking is apparently visible are definitely in aluminum rather than any bonding material or CFRP wrapping?

FWIW, from my perspective as an actually-qualified but non-serving engineer with zero experience in this field the issues at the head tube look like lacquer damage only, on account of their colouration (or lack of) and jagged nature. This isn't ideal as there is evidently strain present in this area to cause this, but I don't think the underlying material has actually failed (yet).

The bottom bracket appears a lot more serious, both because of its shape and more importantly the colouration. As I found out when my frame cracked you'll get a dark deposit at the crack, presumably as the exposed material is abraded by the two sides rubbing together and oxidising. Try wiping the crack with a piece of white bogroll and see if it picks up any black dust from the crack itself or the blackness of the crack seems less after wiping - if so it's almost certainly game over.

As @Johnsco suggests I think a dye penetration test is the way to be 100% certain; my gut tells me the head tube will pass (for now) and the BB will fail.