Frame or fork failures: Lugs? TIG? Carbon

[eric007]

I am aware this may simultaneously incorporate old topics and strong feelings. But my questions are sincere.

There is a concern that some materials in frames and forks may fail at dangerous times, and some express an especial concern that carbon forks or frames may fail abruptly. Let me ask:

1. Do folks worry about other materials failing, such as:
A. TIG welded steel versus Lugged?
B. Welded titanium, as opposed to steel?
C. Thin-walled light steel (such as S3) versus thicker/heavier steel?
2. How many folks, if any, consciously avoid carbon (or some other material) for their frames, forks, seat posts, stems, or handlebars?
3. From your own perspective, what do you think are the safest options?

Thank you for your time.

[Louis]

From your own perspective, what do you think are the safest options?

Staying home on the couch watching TV or in bed sleeping. ;)


Personally, I don't think the criteria you seem to be applying are the correct ones to use. Anything can fail if designed, manufactured or used improperly.

[1centaur]

I would not avoid a material for any application at this point, but I might avoid a new, small maker producing a part at the lightest end of the existing range. If something has been out there a while without reports of problems, I trust the Net and my lesser demands on equipment to tilt the odds in my favor.

[zap]

snipped


From your own perspective, what do you think are the safest options?



Inspect your own kit.

Two years ago I was doing hill repeats and the rear felt much softer than normal. I thought it was my old rear wheel that was about to give up. Some days later as I mounted this TI/Dura Ace kit on my computrainer I noticed a nice crack that was 2mm apart end to end. The ti drive side chainstay peeled like an al can. I have to believe that I was 2mm and 1 second away from getting hurt.

Over the years I found cracks in steel and al frames during inspection.

[bpm]

I have avoided carbon for such things as seatposts, stems, bars, and seat rails. For seat rails, I've seen a few failures and I'm not convinced that is a good application for carbon The weight savings is minimal and the cost difference is huge. For bars, stems, and seatposts, I've avoided carbon not so much that I'm afraid of failure, but because I don't see any real benefit. In many cases, the components are just as heavy, if not heavier, than their aluminum counterparts, are way more expensive, and offer questionable if any benefits in the comfort department.

[csm]

I have avoided carbon for such things as seatposts, stems, bars, and seat rails. For seat rails, I've seen a few failures and I'm not convinced that is a good application for carbon The weight savings is minimal and the cost difference is huge. For bars, stems, and seatposts, I've avoided carbon not so much that I'm afraid of failure, but because I don't see any real benefit. In many cases, the components are just as heavy, if not heavier, than their aluminum counterparts, are way more expensive, and offer questionable if any benefits in the comfort department.

ditto 'cept I ended up with a carbon-railed saddle.

[RPS]

3. From your own perspective, what do you think are the safest options?Everything else being equal (technology, material, quality, etc…), the heavier beefier item will be stronger and less likely to fail.

[rwsaunders]

I just worry about cars getting too close and tires blowing out. Other than that, no much you can do if you maintain your equipment.

[eric007]

[QUOTE=Louis]Staying home on the couch watching TV or in bed sleeping. ;)

Of course, my next post was going to be on titanium versus carbon fiber couches. ;) Thx for all the fine opinions.

[RPS]

Of course, my next post was going to be on titanium versus carbon fiber couches. ;) Thx for all the fine opinions.If you want to incite debate on materials, make it about the use of composites on airplanes like the new Boeing 787 Dreamliner. Some day the lighter-weight plane will undoubtedly save fuel, but for now the significant learning curve is keeping it on the ground.

IMHO such is often the progress with new materials and their new applications.

[RoadRacerVelo]

If you want to incite debate on materials, make it about the use of composites on airplanes like the new Boeing 787 Dreamliner. Some day the lighter-weight plane will undoubtedly save fuel, but for now the significant learning curve is keeping it on the ground.

IMHO such is often the progress with new materials and their new applications.


Not quite an accurate statement. There are carbon planes flying all over the place. The 787 is still awaiting its maiden flight, but because its mostly carbon is not the reason its on the ground. The Boeing 777 and Airbus 380 both rely heavily on composites for much of the aircraft's construction. There are countless composite military aircraft flying.

If carbon fails in any manor or form it is because not enough material was used. That can be for many reasons. Some carbon parts are only made to last for a event or series of events and not engineered to last a lifetime, which it could be if that was the only criteria.

So when it comes to bikes sometimes the lightest may not be the most suitable for everyday use. But that doesn't mean they are fragile or will fail with out notice. There are some carbon bikes on the market that will last a lifetime of use if properly cared for.

In the end I would say choose your carbon bikes wisely.

[RPS]

Not quite an accurate statement. There are carbon planes flying all over the place. The 787 is still awaiting its maiden flight, but because its mostly carbon is not the reason its on the ground. The Boeing 777 and Airbus 380 both rely heavily on composites for much of the aircraft's construction. There are countless composite military aircraft flying.Which part? Did I state that the 787 was the first composite plane? :confused:

It’s more like what Boeing states under advanced technology – “Boeing has announced that as much as 50 percent of the primary structure - including the fuselage and wing - on the 787 will be made of composite materials.” My question to you is then: Has Boeing done this before, or is it new to them on this type of commercial aircraft?

By the way, do you actually think that use of composites had nothing to do with the delays? Do you think that if Boeing had relied on traditional materials for the main structures of the 787 that they would be two years behind schedule “and” now facing an additional delay? Personally I seriously doubt it. Note I’m not questioning the use of composites, just stating that there is normally a learning curve when using a new material “or” using it in new applications.

From Wall Street Journal -- “On Tuesday, Boeing said it had identified problems with the aircraft body near where the wings are attached -- a discovery that would delay test flights and delivery dates to dozens of customers for an unspecified amount of time.”

[Charles M]

Oh for piss sakes...


Lets start an age old and pointless debate that requires generalizing to the lowest end of quality and then expand it to be off topic :beer:

[csm]

Oh for piss sakes...


Lets start an age old and pointless debate that requires generalizing to the lowest end of quality and then expand it to be off topic :beer:

sounds fun. can we somehow relate it to bush and obama?

[RoadRacerVelo]

I hope my post wasn't to off topic. The 787 is behind schedule for a variety of reasons, and no I don't work for Boeing so what the hell do I know except besides the plane being over weight for one (kinda funny because thats why they wanted to use composites) and they need to get it down, a machinist strike for several months, two and they are having trouble with the fasteners they use which attach the carbon fiber panels to the titanium structure, they leaked during the pressure test and they had to replace 8000 of them. I think there are some other issues as well, but those guys know how to work with carbon and that part they have down pat, its other issues that are keeping it on the ground. Its not like they can't mix epoxy and get the mixture right. Sorry I didn't mean to start anything.

And talk about off topic posts! I've never seen so many off topic posts on a cycling forum. Steve Jobs liver transplant, military aviators, Kodachrome and that is just in the last couple days

[Dazza]

I am aware this may simultaneously incorporate old topics and strong feelings. But my questions are sincere.

There is a concern that some materials in frames and forks may fail at dangerous times, and some express an especial concern that carbon forks or frames may fail abruptly. Let me ask:

1. Do folks worry about other materials failing, such as:
A. TIG welded steel versus Lugged?
B. Welded titanium, as opposed to steel?
C. Thin-walled light steel (such as S3) versus thicker/heavier steel?
2. How many folks, if any, consciously avoid carbon (or some other material) for their frames, forks, seat posts, stems, or handlebars?
3. From your own perspective, what do you think are the safest options?

Thank you for your time.

or you are considering it as an option?

I am serious!

[fiamme red]

Staying home on the couch watching TVYou can ride a couch too, you know. I suppose that you could attach a portable TV to it.

http://www.bikeforest.com/cb/

http://www.bikeforest.com/cb/cb.php -- "the true story of Brent and Eivind's travels through Maritime Canada on a human powered couch in the summer of 2002"

[David Kirk]

If you all decide what the one and only best material for a frame is someone shoot me a PM and clue me in. This is the kind of stuff I need to know.

Dave

[Peter P.]

Fun questions!

1. Do folks worry about other materials failing, such as:
A. TIG welded steel versus Lugged?
No; the method of assembly doesn't really matter to me and I think all steels have a slow failure mode so I'll have plenty of warning. At least that's been my experience and I've had several steel frame failures.
B. Welded titanium, as opposed to steel?
I don't have any experience with titanium but I thought I read that yes, it's stronger than steel but cracks propogate faster, too.

C. Thin-walled light steel (such as S3) versus thicker/heavier steel?
I think the answer to this question can be found in the warranties
offered with the ultralight steels.

2. How many folks, if any, consciously avoid carbon (or some other material) for their frames, forks, seat posts, stems, or handlebars?
I do.

3. From your own perspective, what do you think are the safest options?
Steel, in any of the non-ultralight offerings. It may still fail, but it will give you plenty of warning if you inspect your frame regularly. For instance, it's been 8 months since I discovered the downtube on my Reynolds 853 ATB frame was cracked on the underside of the downtube. I check it out after every ride, mark the edges of the crack, and so no further development. My road bike has pin holes in the top tube from sweat. Easy to inspect. It's been at least five years and they haven't evolved.

[cadence90]

If you all decide what the one and only best material for a frame is someone shoot me a PM and clue me in. This is the kind of stuff I need to know.

Dave
Hey, you from Montana, don't you have more important things to worry about, like say the Big Sky falling in??? :D

[fiamme red]

or you are considering it as an option?

I am serious!Happy birthday, Dazza. :beer:

[Tobias]

If you all decide what the one and only best material for a frame is someone shoot me a PM and clue me in. This is the kind of stuff I need to know.

DaveIt’s called TITANIUM. Stronger and lighter than steel, never corrodes, doesn’t have to be painted but can be, and unlike carbon can bend without fracturing and survive being left in a very hot car. The only problem for the industry is that when designed and built right it will last for generations.

[Marcusaurelius]

It’s called TITANIUM. Stronger and lighter than steel, never corrodes, doesn’t have to be painted but can be, and unlike carbon can bend without fracturing and survive being left in a very hot car. The only problem for the industry is that when designed and built right it will last for generations.


Well titanium costs signifcantly more than steel and a lugged steel frame has something extra that a tig welded titanium frame will never have. I think there's just something inexplicably exciting in a lugged steel frame and steel fork.

[eric007]

Dazza -- why yes, I do ride a bike. Slowly and badly, to be sure.

Oddly, I know people who work on the 787. I think they're good people. Cautious, but that's a good thing.

I think as I age, and given that I am not likely to spend my spare time looking for tiny cracks in a fork, I have been trending toward lugged steel. But I was curious how irrational y'all might consider my concerns.

And Dave -- if your name is David Kirk, then the one and only best material for a frame is brazed steel. And don't start thinking otherwise.

Thank you all for your time. -- E

[zap]

B. Welded titanium, as opposed to steel?
I don't have any experience with titanium but I thought I read that yes, it's stronger than steel but cracks propogate faster, too.



Try lightning fast.

Titanium frames scare me.

Carbon composites rule.

[RPS]

Try lightning fast.

Titanium frames scare me.

Carbon composites rule.Playing Devil’s advocate: Has anyone ever found a crack in a steel spoke in time to stop it from suddenly snapping in two?

Obviously there are differences in material failure modes, but it’s not always about the material itself. Much of what we observe may have more to do with how the material and its surrounding is loaded at the time failure starts.

[Repack Rider]

What's wrong with this picture?


http://i419.photobucket.com/albums/pp271/repackrider/Miscellaneous%20images/serotta1.jpg


I dunno, ya think it's still ridable?

http://i419.photobucket.com/albums/pp271/repackrider/Miscellaneous%20images/serotta2.jpg

[Tobias]

Wreck a carbon frame like that and you won't ride it at all; it will be in many pieces.

[Dazza]

It’s called TITANIUM. Stronger and lighter than steel, never corrodes, doesn’t have to be painted but can be, and unlike carbon can bend without fracturing and survive being left in a very hot car. The only problem for the industry is that when designed and built right it will last for generations.


what I find incredible is that a lot of people think Titanium is fatigue proof.
I got some frames lying around here that show other wise.

People, don't get hung up on it all
get a bike
learn to enjoy riding
and ride as much as you can
long rides
long fixie rides are just ace
long ride in the mountain
a spin around the block
life is too short to hang about in coffee shops or watch TV

[dd74]

I bent a Columbus Spirit frame much like the Serotta above. I won't ride it again.

[RPS]

what I find incredible is that a lot of people think Titanium is fatigue proof.
I got some frames lying around here that show other wise.
I don’t recall anyone suggesting that Titanium doesn’t fatigue, but I may have just missed it.

For the non-technical, Titanium has a very generous endurance limit – typically in the order of 0.50 to 0.65 of the ultimate tensile. As long as stresses are kept below that (which isn’t too difficult unless the builder is trying to lightweight the frame excessively or doesn’t know how to use the material), fatigue shouldn’t be an issue. A good ti frame should last longer than most of us under normal use.