Broken Steel, I Guess I Was Lucky.

[FrankCrank]

Had an ally framed folder snap in two some time back, and like the op came away unscathed - very lucky. I think it must be very rare for a steel frame to break, just thought of them as being able to give more warning of imminent failure - maybe time for a rethink.

Perhaps having brazed on gear bosses is not a good design, and as for weld failures in general it's the adjacent metal that usually fractures, rather than the weld itself, as appears to be the case here.

 

[SkipdiverJohn]

@SkipdiverJohn will come round later......he’ll get 1000s more miles out of that bike

Er, no, I would count my blessings that I didn't have a nasty crash and scrap the frame. It doesn't appear to have been very well built anyway if the tube pulled out of the lug. If the joint was clean and properly made during fabrication it would take a hell of a lot of force to pull it apart. Braze isn't as strong as weld, but it's pretty strong all the same if done right.
I've had a chainstay fail myself on a 1991 Raleigh Pioneer frame, which is pretty rare for those as they weren't minimally built for lightness. I've replaced that one with another Pioneer frame a year younger. Failures usually occur as a result of a stress raiser, and it fatigues over a very long period. The downtube has to resist all sorts of different forces, so it is heavily loaded.

 

[Darius_Jedburgh]

You don't think that the main problem is the lug giving way due to poor construction. That would increase pressure on the gear boss area. There isn't much sign of rust there so possibly that was not the original cause of the problem. The lug on the seat tube looks more likely to be the first to give way.

 

[twentysix by twentyfive]

The lug on the seat tube looks more likely to be the first to give way.

Yep - that joint hasn't been any good for quite a long time.

 

[biggs682]

Couple of jubilee clips and it's repaired what's wrong with you guys

 

[AndyRM]

I'm with @biggs682 - that'll buff out.

 

[AndyRM]

Jesus. That could have been very nasty!

 

[SkipdiverJohn]

Jesus. That could have been very nasty!

And that's in a material where catastrophic failures are very rare, especially sudden unexpected ones. I would still trust steel over aluminium, and especially over carbon fibre, every day of the week.

 

[Darius_Jedburgh]

And that's in a material where catastrophic failures are very rare

I don't think its the material - steel - that has failed. I still think poor construction of the lug joint that is responsible. Down tube will have cracked due to excessive load placed on it.

 

[fossyant]

Fair bit of corrosion inside that frame .

That's what I spotted too. Both my steel bikes were sprayed with Waxoyl, GT85 and other aerosol oils. Refurbing my Ribble in January, I could only smell oils from the inside of the frame.

 

[bagpuss]

Glad you escaped serious injury
I have had various frames fail over the years,mostly through heavy use /wear and tear . One frame failed on a bottle boss {Down tube}. Had the tube replaced under warranty .Sometime later the same frame cracked on the seat tube just above the b/b lug .Again frame tube replaced . Since then the threads on the b/b have worn out . Looking at having a sleeve fitted or glueing a sealed unit in with epoxy resin .
Frame was built with 531 competition tubing to my spec , With hind sight I should of had 531 ST which would have stood up better the heavy use .

Even had a titainium frame fail on the top tube , which was replaced under warranty .

 

[SkipdiverJohn]

I don't think its the material - steel - that has failed. I still think poor construction of the lug joint that is responsible. Down tube will have cracked due to excessive load placed on it.

It's difficult to assess the reason for something failing without very clear,close-up shots where you can examine the surfaces of the failure for clues how it occurred.
The steel clearly has failed, but I get your point all the same - the root cause may be in the build not the actual material being substandard.

 

[biggs682]

Since then the threads on the b/b have worn out . Looking at having a sleeve fitted or glueing a sealed unit in with epoxy resin .

I bought a frame That a previous owner glued cups in place , couldn't budge them so had Lee Cooper melt them out then cut and shut the bottom bracket and re do the threads ended up as good as new .

 

[Darius_Jedburgh]

It's difficult to assess the reason for something failing without very clear,close-up shots where you can examine the surfaces of the failure for clues how it occurred.
The steel clearly has failed, but I get your point all the same - the root cause may be in the build not the actual material being substandard.

👍

 

[Chris S]

@IanSmithCSE what make of bike was it?