Frame failure experiences

bikeworkshop

Senior Retro Guru
I'm sure there's loads of experience of frame failure amongst posters here. I've looked at hundreds over the years so I thought we could share our knowledge👍

I've seen plenty of beautiful 60s racers- paint in good condition, but holes in the stays rusting from the inside.
Early brazed mtbs too, lugged or brazed.

Its hard to wash out all the flux from brazing - that doesn't help.
Some framebuilders didn't do a good job, some didn't care as it won't matter for a decade.
Some craft builders weren't even aware of the problem🤣

Sometimes the steel near the dropouts becomes granular with age - makes replacing the dropout a real challenge!

Early alloy frames are prone to fatigue - initially they were guaranteed for only 2 years!
Later alloys address this issue - as far as they can. I don't think it ever goes away though.
It's part of the reason alloy frame tubes got bigger and the bikes got stiffer.

A little used alloy frame will be much better than a well used one.
A cheaper frame would probably outlast a race- level model.

Titanium could last for ever... but rarely does.
The material shares qualities with both steel and alloy, leading to fatigue cracks along the tubes or through the joints (as opposed to across the tubes and along the joints)
I put this down to our lack of historical experience with ti.
Steel we know well.

Carbon ought to be stable, being a mesh of fibres set in epoxy - but some low quality epoxies weaken and crack, and many carbon frames aren't built to last anyway so occasional impacts can kill them quick.

My favourite carbon frame failure was a customer put his fancy summer bike in the shed over winter, and when he got it out in spring it had broken in two!
The dealer told him it was overexposure to heating/cooling cycles.
Love it.😍

And we all know of bonded frames coming unbonded. Often corrosion on the tube breaking the glue away, rather than the epoxy failing.
(Seen a few of them too, although if course people bring old bikes in to us because there's a problem, so I'm shown many more broken bikes than museum pieces🙄)

Brazed frame tubes can pull out of the lugs too if the brass didn't achieve good flow at the molecular level...see the flux issue above🤔
 
I've only snapped 1 frame in my life, alloy full sus, not designed for 135mm jnr T forks. gave way at the head tube to top tube weld. welded in a gusset and kept on riding it, eventually it failed at the suspension pivot. :)

seen lots of others, but that one is personal.
 
I've only snapped 1 frame in my life, alloy full sus, not designed for 135mm jnr T forks. gave way at the head tube to top tube weld. welded in a gusset and kept on riding it, eventually it failed at the suspension pivot. :)

seen lots of others, but that one is personal.
Early days of triple clamps tore a few headtubes off!
I can remember selling jnr ts to a guy, he was back to buy a new frame about 2 weeks later.

Azonic steelhead iirc

No one ever blamed the fork though, just their own fault - and hardcore riding😄

TCs are less popular now as I imagine a tapered steerer and through axle can give the same strength and stiffness.
 
In bikeworkshop's commercial experience, the common causes of a broken frame are disappointingly mundane:

Wrong size seatpost,
Too little post insertion
Riding a loose headset for years
Loose bb cups
Wrong axle length in rear dropouts
Chain gouge on the stay
Basket rubbing on the headtube
Broken bearings caught between the steerer and headtube
Attempted theft
Friday-night bikehater Vandalism
Crashing
 
Never broke one but almost every Mountain Cycle San Andreas has damage from where the forks have hit the frame, Mine didn't and I never fitted big triple clamps forks for mainly that reason.
Id just like to say though that Failure in regular use is super rare, and usually on a massively undermaintained bike, where the warning signs like cracking and creaking have been ignored.
I know but I was just looking to buy my forever bike :p
 
Early days of triple clamps tore a few headtubes off!
I can remember selling jnr ts to a guy, he was back to buy a new frame about 2 weeks later.

Azonic steelhead iirc

No one ever blamed the fork though, just their own fault - and hardcore riding😄

TCs are less popular now as I imagine a tapered steerer and through axle can give the same strength and stiffness.
indeed they do. only crazy long travel downhill type stuff needs it now. love my Jnr T's, they were pretty much the easiest way to that travel back then (you could do Z1's but they wearn't all that). I knew they'd probably kill that frame, I'd already bought something with appropriate gussets for them before it gave way.

actually, I did snap that frame at the seat post (13" jump frame with a 13" seat post will do that, but you got to ride to the trails round here and dropper posts didn't exist), it got a steel collar and it's still going strong some 20 years later.
 
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