Is this cracked titanium frame safe to ride?
#176
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I am a metallurgist and ride titanium. This head tube has already failed. It's not maybe going to fail, it has. Titanium is a tough material, so you have to ask yourself why? I don't see any blunt force evidence, so it is likely to be a stress crack or crevice crack corrosion. If it's a stress crack, welding will likely fix it, If its crevice crack corrosion, welding will likely not fix it. The head tube and frame are safety critical items so let's do a risk assessment
Are the medical deductibles and possible lost time with those associated costs cheaper than the repair or scraping the bike. Make no mistake about it, the head tube has already failed, and no life-threatening accident has occurred. smd4 has already point out that this is likely the result but that gift of discovering the failure before injury has already occurred. I put the probability of injury due to catastrophic failure at 10-20%. Now if you continue to ride the bike, please bear in mind that you are doing what we call self-insuring. Keep in mind it will fail further, no question in my mind. You are betting the medical deductibles, and lost function to be an acceptable risk against the cost of repairs.
Me, I would likely replace the head tube or scrap the bike. My deductibles are $7,000 worth of self-insurance plus lost money because of hiring stuff done. Insurance would cover the funeral costs. That hardly seem worth it against a possible $200-$600 repair bill. $600/$12000 is 5% and I put the injury probability at 10-20%. My client says pass.
Are the medical deductibles and possible lost time with those associated costs cheaper than the repair or scraping the bike. Make no mistake about it, the head tube has already failed, and no life-threatening accident has occurred. smd4 has already point out that this is likely the result but that gift of discovering the failure before injury has already occurred. I put the probability of injury due to catastrophic failure at 10-20%. Now if you continue to ride the bike, please bear in mind that you are doing what we call self-insuring. Keep in mind it will fail further, no question in my mind. You are betting the medical deductibles, and lost function to be an acceptable risk against the cost of repairs.
Me, I would likely replace the head tube or scrap the bike. My deductibles are $7,000 worth of self-insurance plus lost money because of hiring stuff done. Insurance would cover the funeral costs. That hardly seem worth it against a possible $200-$600 repair bill. $600/$12000 is 5% and I put the injury probability at 10-20%. My client says pass.
Last edited by KPREN; 09-06-22 at 07:21 AM.
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#177
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Seven pages. Seven...pages.
And my initial question still hasn't been answered in any serious way (Although someone mis-interpreted that question into "advice"). We've got lots of predictions of end-result catastrophic failure, hoped-for good dental insurance, impending death...But no theories about the actual process of frame failure that will lead to all of this.
Seven pages.
"Crack, crash." Uh huh.
What do you think that means? Do you think the crack will propagate the entire length of the head tube? If so, will it then roll open? Or will the front end get so wobbly that the rider will then deicide to stop? Will the crack stop at the reinforcing ring at the top?
Lots of fear mongering. Not much actual thought.
(Why should I be surprised? People still think my rims are going to explode at 140 psi).
And my initial question still hasn't been answered in any serious way (Although someone mis-interpreted that question into "advice"). We've got lots of predictions of end-result catastrophic failure, hoped-for good dental insurance, impending death...But no theories about the actual process of frame failure that will lead to all of this.
Seven pages.
"Crack, crash." Uh huh.
What do you think that means? Do you think the crack will propagate the entire length of the head tube? If so, will it then roll open? Or will the front end get so wobbly that the rider will then deicide to stop? Will the crack stop at the reinforcing ring at the top?
Lots of fear mongering. Not much actual thought.
(Why should I be surprised? People still think my rims are going to explode at 140 psi).
Tell you what--you run the experiment that shows that the complete failure of the head tube while riding isn't by definition a really bad thing. Knock yourself out--literally.
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#181
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Prove the crack wont lead to catastrophic failure.
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But I will add that, while there is indeed "nothing magical about welding Ti," it must be handled rather differently than other metals. Very differently, in fact.
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#185
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Meh, welcome to the internet... Hands down one of the worse BF members I've encountered in my 9 years here..
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I actually didn't even know he insulted me like that until I saw your quote. I have him on block, he knows he is blocked by me yet he keeps posting Q's to me and now insults.. Flippin' stalking weirdo...
Meh, welcome to the internet... Hands down one of the worse BF members I've encountered in my 9 years here..
Meh, welcome to the internet... Hands down one of the worse BF members I've encountered in my 9 years here..
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I unhide that post to see what else he said and he is not a very trustworthy person. He partially quoted what I said to intentionally take it out of context and make it sound like I was ok with someone riding that bike.
Sadly some people are just like that.. Luckily members like him are in the extreme minority here at BF. Most members here are, and always have been, very friendly and and extremely helpful.
Sadly some people are just like that.. Luckily members like him are in the extreme minority here at BF. Most members here are, and always have been, very friendly and and extremely helpful.
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#190
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.
...what's weird to me, in this thread, is that this sort of stress cracking in a bicycle head tube is a relatively common occurrence on steel frames. Frame guys who work on/with steel see it all the time, and the proper repair is invariably to replace the failed head tube. That's the sort of repair you can stand behind with a guarantee. Even in a material as easily welded as steel, I know of nobody who does this professionally who would just run a weld bead on a head tube that has already failed once, and call it good.
I had a very tiny crack in the bottom of the lower head lug on a Raleigh Pro once. It was on a fairly nice early one, that I wanted to repaint, and did not involve the tube, only the lug into which it was inserted. You could barely see it, but it was definitely cracked there. That was repaired with a weld, but not without first cutting a small V, to insure full cleaning and penetration to the bottom of the crack.
Certainly that frame is repairable. As already recommended, either the original company, or another bicycle frame person who regularly works with this metal will replace the failed tube for you. But unlike the best things in life, it's not free.
...what's weird to me, in this thread, is that this sort of stress cracking in a bicycle head tube is a relatively common occurrence on steel frames. Frame guys who work on/with steel see it all the time, and the proper repair is invariably to replace the failed head tube. That's the sort of repair you can stand behind with a guarantee. Even in a material as easily welded as steel, I know of nobody who does this professionally who would just run a weld bead on a head tube that has already failed once, and call it good.
I had a very tiny crack in the bottom of the lower head lug on a Raleigh Pro once. It was on a fairly nice early one, that I wanted to repaint, and did not involve the tube, only the lug into which it was inserted. You could barely see it, but it was definitely cracked there. That was repaired with a weld, but not without first cutting a small V, to insure full cleaning and penetration to the bottom of the crack.
Certainly that frame is repairable. As already recommended, either the original company, or another bicycle frame person who regularly works with this metal will replace the failed tube for you. But unlike the best things in life, it's not free.
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This is nonsense, and I think the fact that they knowingly sold a cracked bike without disclosing it says enough about their credibility that I wouldn’t bother asking them any more questions.
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You've been given the same answer in several forms--once a critical part fails catastrophically while the bike is in motion, we really don't know what might happen because a whole bunch of different parts are going to be subjected to forces they were never designed for. We aren't stupid enough to try this experimentally so you're demanding a specificity that's impossible. Plus, the question is obviously not being asked in good faith because you know this.
All this because you're still mad most people think you're over-inflating your tires? Get over it.
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The following morning I discovered the reason for the too-good-to-be-true asking price: The frame is cracked around the headtube. I contacted the seller and he replied: "That does not compromise the structure of the head tube, according to the manufacturer. If it completely cracks, which will not, I’ll refund you the money, or you are welcome to return it. Your call"
Given this, what basis do you have to believe the nonsense the seller is telling you?
Last edited by njkayaker; 09-06-22 at 10:22 AM.
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#194
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Second, but less importantly, I regularly ride Vittoria tyres, pumped to the max inflation on the sidewall of 130psi, with no adverse results. I do this because I am quite a large person, and heavy as a result. Also, it helps me to go marginally faster on my typical riding surfaces. AS I slow due to aging, I need some kind of belief in that tiny trick, to make me feel better about the whole situation.
But really, try the "you people !!" thing. I think you'll find it fits with your general style and demeanor here.
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