Breaking Carbon and Aluminium

howierart said:

I once had a terrible disaster involving my 1999 Specialised Allez. Hit a pothole in the road and the aluminim forks snapped clean off on both sides. This led to rather an unpleasant head injury and a tarmac haircut! Also recently I heard what sounded like a gunshot at the front of my Coppi, again after catching a pothole in the road. It was such a shake that it reset the computer. Though after investigating I cant find any flaws in the carbon forks, Alloy handlebars etc.. Should I be worried? Anyone want to share thier stories of bike frame and fork failure?

Stuff breaks.More frequently when falling into big potholes.Pay better attention.

Inspect reaaal close including some stong jerks on the steerer/fork/bars. You sure the gunshot sound came from the bike (could it have been something in the ground, manhole cover or the like)? Haven't experienced anything like that. Maybe the stem slipped a hair and made the sound...hmm. Careful riding the thing first few times out. 😕

RC2 said:

Inspect reaaal close including some stong jerks on the steerer/fork/bars. You sure the gunshot sound came from the bike (could it have been something in the ground, manhole cover or the like)? Haven't experienced anything like that. Maybe the stem slipped a hair and made the sound...hmm. Careful riding the thing first few times out. 😕

Yeah Ive checked real close, took the front end apart and cant seem to see any cracks or anything. Also Ive been 200 miles on it since and it seems ok. THough there is always the fear of something happening - hence this post! With regards to boudreaux's comments - I do pay very careful attention, though I dont want to be staring at the road looking for potholes in heavy traffic when both the above incidents occured. Maybe the roads where I live are badly kept, but I spend my life dodging potholes.

Last time I heard a gunshot from hitting a hole (it was in the grass, when I had to swerve off the road to avoid a car that crowded me after being spooked by oncoming traffic) it was a broken spoke. I know it sounds obvious, but did you check all your spokes?

Don't mess with this stuff. If you can't find anything that may have caused the sound, take everything apart and either inspect it or have it inspected by a shop. I'd choose the latter.

I just saw some stress tests done on aluminum forks, where exactly did yours fail?
Since aluminum and carbon are brittle, they will fail quickly when they go. If the cracks were on the inside of the fork you might not be able to see them. You should check your fork over every couple rides for a while to see if you can spot any cracks forming. If there is a crack it will expand with each loading cycle, whenever the fork flexes. It will probobly appear on the back side/bottom where the fork is in tension.
Good luck with the potholes.

spacefuzz said:

I just saw some stress tests done on aluminum forks, where exactly did yours fail?
Since aluminum and carbon are brittle, they will fail quickly when they go. If the cracks were on the inside of the fork you might not be able to see them. You should check your fork over every couple rides for a while to see if you can spot any cracks forming. If there is a crack it will expand with each loading cycle, whenever the fork flexes. It will probobly appear on the back side/bottom where the fork is in tension.
Good luck with the potholes.

When my forks snapped they snapped about an inch from the top on both blades. One of the breaks was clean, the other was kind of hanging off. I bloomin potholes, spent yesterday thinking shold I swerve into traffic to avoid them or hit em! We need new roads round here!

howierart said:

When my forks snapped they snapped about an inch from the top on both blades. One of the breaks was clean, the other was kind of hanging off. I bloomin potholes, spent yesterday thinking shold I swerve into traffic to avoid them or hit em! We need new roads round here!

I always go for the swirve into the traffic approach, it pays better than just plain writing your bike off with the potential of going under a fast moving vehicle anyhow, plus cars have insurance potholes don't 🙂

Atleast a driver would be aware that there was an hazard in your path plus they should be enough distance between you anyhow, i ride in the middle of the road anyhow, since most the potholes tend to be at the roadside.

I hit a pothole yesterday, and i was terrified as the rear wheel past over it. since there was an almighty creak from the rear of my composite, i thought that it was going to collapse, now i have a problem with my front wheel.

when you spin the cosmic it sounds like there is something moving inside the rim but it looks okey! has anyone experienced anything like this, you can imagine once the wheel is moving at speed the sound stops..

Howie did you pass through wigan yesterday, hindley to atherton... if so are you aware that you almost killed a guy on a mtb who was trying his hardest to catch you 😄 if you did, what do you think about the road through hindley town centre onwards, dreadful really in need of resurfacing.

Howie did you pass through wigan yesterday, hindley to atherton... if so are you aware that you almost killed a guy on a mtb who was trying his hardest to catch you 😄 if you did, what do you think about the road through hindley town centre onwards, dreadful really in need of resurfacing.[/QUOTE]
Ha ha ha local man, no on Saturday I was north of Preston around Beacon fell, LOvely sunny day too marvelous 70 mile run! Though I do sometimes skirt the edges of Wigan. Mainly in the Hills round Appely Bridge / Standish. Also en route to see my brother in Manchester. Its better to go Wigan way than down the East Lancs road - thats hell on a bike.

howierart said:

Howie did you pass through wigan yesterday, hindley to atherton... if so are you aware that you almost killed a guy on a mtb who was trying his hardest to catch you 😄 if you did, what do you think about the road through hindley town centre onwards, dreadful really in need of resurfacing.

Ha ha ha local man, no on Saturday I was north of Preston around Beacon fell, LOvely sunny day too marvelous 70 mile run! Though I do sometimes skirt the edges of Wigan. Mainly in the Hills round Appely Bridge / Standish. Also en route to see my brother in Manchester. Its better to go Wigan way than down the East Lancs road - thats hell on a bike.[/QUOTE]
Local man i am, i often head off up standish up to leyland way and back around but i usually always find myself heading towards rivington pike cause there are some brilliant climbs plus its the only real landmark i know and i head for it to find my way home. i usually find myself out on the road for aslong as possible with no direction but to follow the road to whereever it leads me.

i have often wanted to spend time on and around ashurst beacon, the last time i went though i ended up in southport 😄 via skem ormskirk > southport back to preston niceday and it was fun.

have you road the roads in euxton between chorley and leyland these are my favourite roads, since the roads down here in wigan would be better cobbled since the tarmac is in terrible condition.

spacefuzz said:

I just saw some stress tests done on aluminum forks, where exactly did yours fail? Since aluminum and carbon are brittle, they will fail quickly when they go.

As a sidenote, L. Zinn, as good a name in bike tech as any, points out that today's carbon forks seem to hold up better in the long run than their steel counterparts. There's probably a lot of factors contributing to that observation, but it's worth keeping in mind. It's also worth noting that where reputable manufacturers are concerned, average-weight carbon forks remain a great choice for most.

lokstah said:

As a sidenote, L. Zinn, as good a name in bike tech as any, points out that today's carbon forks seem to hold up better in the long run than their steel counterparts. There's probably a lot of factors contributing to that observation, but it's worth keeping in mind. It's also worth noting that where reputable manufacturers are concerned, average-weight carbon forks remain a great choice for most.

LOKKY! Haven't heard from you in months.
Do you really know Boudreau?
Where did you read about LZ and CF Forks?'
Roland Della Santa says he won't ride in a paceline with anybody who has a carbon fork - says he's seen too many of them spontaneously shatter... could be just anti-hype for steel forks.

howierart said:

I once had a terrible disaster involving my 1999 Specialised Allez. Hit a pothole in the road and the aluminim forks snapped clean off on both sides. This led to rather an unpleasant head injury and a tarmac haircut! Also recently I heard what sounded like a gunshot at the front of my Coppi, again after catching a pothole in the road. It was such a shake that it reset the computer. Though after investigating I cant find any flaws in the carbon forks, Alloy handlebars etc.. Should I be worried? Anyone want to share thier stories of bike frame and fork failure?

How much do you weight ?
You might want to think about getting a steel fork...

DiabloScott said:

LOKKY! Haven't heard from you in months.
Do you really know Boudreau?
Where did you read about LZ and CF Forks?'
Roland Della Santa says he won't ride in a paceline with anybody who has a carbon fork - says he's seen too many of them spontaneously shatter... could be just anti-hype for steel forks.

Wazzup Scott? Changed jobs, moved (Berkeley to Oakland, no biggie), and other things--fell off the forum wagon. Back in the *typing* saddle, never having left the Fizik one. What can I say? I must have missed you guys.

Boudreaux? I wish to god I knew the man personally, so I could compare the real thing with the mythologized vision I've enjoyed for all this time now. I'd likely be disappointed, so it's probably for the best.

The Zinn quote about carbon versus metal forks came from one of his VeloNews columns or QAs, sometime within the last year or two, I think. I'll see if I can find it.

lokstah said:

Boudreaux? I wish to god I knew the man personally, so I could compare the real thing with the mythologized vision I've enjoyed for all this time now. I'd likely be disappointed, so it's probably for the best.

The swamp alligators have been drooling at the thought of some fresh blue smurf meat.Welcome back. 😉

boudreaux said:

The swamp alligators have been drooling at the thought of some fresh blue smurf meat.Welcome back. 😉

Hark, thy fair Juliet speaks.

😎