Wannabe Posted January 9, 2011 Posted January 9, 2011 (edited) When taking my bike of the stand this afternoon for my afternoon ride, I felt the seatpost move. Upon closer investigation I noticed this HUGE crack around the top of the seat tube. Looks like its been there for a while, but got worse when I hit a ditch in the road on my last ride. It was hidden under the yellow reflective tape I had around the seat tube.It is a 7005 Heat Treat Alu frame. I know that this cannot be repaired, but maybe something else can be done to save this frame.I'm insured with OutSurance, anybody aware if this is claimable or not? Edited January 9, 2011 by Wannabe
The_Break Posted January 9, 2011 Posted January 9, 2011 How old is that frame? The frame cracked in what is called a stress concentration in engineering lingo. This specific failure is due to either poor welding or a poor design of the wall thickness and weld. Must add though that it is difficult to predict stress concentration failures of this type. Very difficult. A really good welder may be able to fix it, but then you will probably pay more than what the frame is worth with the welding and painting required. My only hope is to try and see if the frame manufacturer would be willing to warranty the frame as it is clearly due to a designed/manufactured in stress concentration.
Capricorn Posted January 9, 2011 Posted January 9, 2011 time to get something out if u follow my drift
Wannabe Posted January 9, 2011 Author Posted January 9, 2011 Break, It is an Omega frame, manufacturers closed down looonngg ago, so that avenue cannot be explored. Frame is about circa 2005, old in alu terms.
Capricorn Posted January 9, 2011 Posted January 9, 2011 the break, easy on slamming the manufacturer/engineering/assigning damning causes to assumed guilt parties. There is also such a thing as fatigue failure, and if that area has surpassed it's best guestimated life cycle, then it's no one's fault really. Where is this stress concentration you've stated is the cause for the failure?
bikemonster Posted January 9, 2011 Posted January 9, 2011 Just put the tape back on so you can't see the crack. I'm sure it'll be fine. Disclaimer: Do not under any circumstances follow the above advice!
Wannabe Posted January 9, 2011 Author Posted January 9, 2011 Just put the tape back on so you can't see the crack. I'm sure it'll be fine. Disclaimer: Do not under any circumstances follow the above advice!If only it was as simple as that. Maybe I must glue it, put the tape back and then sell the frame.
Eugene Oppelt Posted January 9, 2011 Posted January 9, 2011 Just put the tape back on so you can't see the crack. I'm sure it'll be fine. Also known as the powerbalance placebo effect...
Eugene Oppelt Posted January 9, 2011 Posted January 9, 2011 I'm not much of an engineering mind or bike tech - time for a new fiets, I say... An exit is also an entrance to something new... All the best, Wannabe!
The_Break Posted January 9, 2011 Posted January 9, 2011 (edited) the break, easy on slamming the manufacturer/engineering/assigning damning causes to assumed guilt parties. There is also such a thing as fatigue failure, and if that area has surpassed it's best guestimated life cycle, then it's no one's fault really. Where is this stress concentration you've stated is the cause for the failure? One also designs for fatigue so that would still fall under the design responsibility. And you also design for fatigue in weld design. Notice how the crack has a small arc shape at the top of the one pic where it follows the edge of the weld. This is the stress concentration and where the crack propagated from. If you look at the loads involved this is also the higest stress area on the seat tube. A properly designed frame will not make guesstimates. We get simiar parts back from warranty claims in my field and we replace these with no questions asked. We then perform a redesign, test and introduce onto the market. Pity the company has closed down. Edited January 9, 2011 by The_Break
Eugene Oppelt Posted January 9, 2011 Posted January 9, 2011 Brilliant comments, The Break...I'm learning.
Wannabe Posted January 9, 2011 Author Posted January 9, 2011 I'm not much of an engineering mind or bike tech - time for a new fiets, I say... An exit is also an entrance to something new... All the best, Wannabe! There's a Solis Magma frame I've got my eyes on. Should everything pan out, I might just procure it. A decent "something new", don't you think?
Eugene Oppelt Posted January 9, 2011 Posted January 9, 2011 There's a Solis Magma frame I've got my eyes on. Should everything pan out, I might just procure it. A decent "something new", don't you think?Just wanna see you back on an iron horse, man... All the best with the pursuit of the Solis Magma!
Capricorn Posted January 9, 2011 Posted January 9, 2011 (edited) actually the break, all companies that design make best guestimates, and if you're an engineer, you should know this all too well. FEA, bench tests, and the marin factors all are best guestimates as real life conditions are at best SIMULATED, unless you've managed to figure out what no one else has managed todate That best guestimate phrasing does not imply a simpletons versionf of guess at all, and an engineer will automatically understand the context for it's usage. Also, that 'arc' you referred to. I assume you referring to the first photo. That's in the HAZ, where yes, HAZs typically are stress concentrators. But given that this bike already has a nick name, ie The Red Rocket, Wannabe musta ridden this thing like his favorite gf, so yes, it's more than likely he has found this particular components fatigue failure limit. If this were a brand new frame, then by all means: flame to your hearts content. I simply believe that that is not warranted in this instance. Where is JB when u need him out of curiosity, what work do you do ? Edited January 9, 2011 by Capricorn
flymango Posted January 9, 2011 Posted January 9, 2011 There's a Solis Magma frame I've got my eyes on. Should everything pan out, I might just procure it. A decent "something new", don't you think?Looks like you're gonna be asking for forgiveness, and not permission
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