Cracked frame. Why?

sogood said:

The problem with this statement lies with the definition of "well designed". If by well designed meant that they are all designed to the same durability specification, then they should all fail at the same time.

Agreed, wouldn't frames like Cannondale's CAAD series, which test to a very high standard on efbe's fatigue tests, be expected to have similar longevity to high-quality frames of other materials?

Thanks for all the feedback.

Whatever has happened, it seems clear that cracks and damage to a frame can be hidden and/or lie dormant.

I'm not sure that the bike wasn't set up correctly (headset too tight?), as I have two very good bike shops, and I trust both of them. Which suggests either a manufacturing defect which has manifested itself over time, and/or some kind of stress/crash which has caused failure in the frame, once again, over time (though even without use).

In any case, I'll try and chase this up with Gios to see if they don't want to have a look at it in the hope that we can get a bit further towards finding a cause.

Sprint2Win said:

Maybe the diameter of that headset was too large for the headtube?

Very possible. They might not have reamed the head tube.

I've cracked two heads, both steel frames. Neither bike was crashed. For the thrid steel frame, I had a stronger head put in. That bike was crashed and had the top tube and down tube replaced. 2 years later the same frame cracked on the down tube not far from the head.

bobbyOCR said:

Very possible. They might not have reamed the head tube.

that is very possible, indeed.

perhaps we are seeing the results of another "2-hour" build job.

not only should the head tube be reamed, the inside edge should be deburred/radiused.

as a wild guess (and nothing more) i'ld say the culprit is simply a lack of enough material. in the quest for less weight, durability is often the first thing to be sacrificed.

My mate has a Giant OCR2, 2002 model ( I think) it is white with Red on the down-tube. He has a crack in the right-hand chain-stay, about one inch aft of the wishbone/crosspiece (the piece to the rear of the BB).
The worst thing is, he bought it second-hand and Giant has a lifetime Frame Warranty only for the original purchaser.
Does anybody have any experience of aluminium frame repairs...can this be welded safely? or does the local application of intense heat, weaken the alloy...I remember a few years ago, a mate of mine had a ute (US- Pick-Up) with an aluminium tray, and he told me that welding Aluminium is bloody expensive and harder than steel...

Sprint2Win said:

Maybe the diameter of that headset was too large for the headtube?

Yes, an overly-tight interference fit results in high hoop stress on the headtube without even riding the bike. If you look closely inside the headtube under bright light, any evidence of white powdery corrosion along the crack would confirm. OTOH, I could be all wet with this too....just guessing. The reason I thought of the stress corrosion cracking was that you said the failure occured during storage in a cellar. Damp environments like unheated cellars accelerate corrosion of course.

Aussie Steve said:

Does anybody have any experience of aluminium frame repairs...can this be welded safely? ...

I'm no expert, and I could therefore be wrong, but I was told after I cracked a Specialized that only thick bits can be repaired properly, such as BB shells, and some thicker dropouts. The dude went on to say that thin bits, such as the most of a tube section, are too thin to stand the 2nd heat appliaction?? On such a cheap frame it's probably not worth it -- he should be able to pick up a 2nd hand alu frame in good condition for under well $300

531Aussie said:

On such a cheap frame it's probably not worth it -- he should be able to pick up a 2nd hand alu frame in good condition for under well $300

Not sure what you mean here .. the Cinquantenario is the top Alu frame in the Gios line, and is up in the 1100 - 1200 Euro range, plus 400 for the carbon fork. This is the frame that Roberto Heras won the Vuelta on in his Kelme days. I doubt very much I'd get a frame like this for under $300 - though after this experience, doubt very much I'd ever buy a 2nd hand frame again.

I had a friend who cracekd his TCR 2. He got it welded, but the welder told him not to put it through too much stress. I think re-welding an Al frame creates a weak joint which would probably fatigue quickly.

Try and get the GIOS welded. I am sure that area of the head tube won't cause too many problems if it is re welded. Just make sure the tube is prepared properly.