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Is this frame fixable?
Tonight, when I arrived at the park for our weekly club ride, someone had left some bike parts with a handmade sign stating "FREE", leaning against a fence. In addition to the assorted tubes and tires, (which I also grabbed), was this Cannondale CAAD4 R3000 frame. I believe it to a model year 2000.
The issue with the frame appears to be a sizable dent in the top tube. It looks like something fell on it. Opinions? https://lh5.googleusercontent.com/-e...2/P1020419.JPG https://lh3.googleusercontent.com/-4...2/P1020418.JPG |
Can you get an inner tube in there? Inflate it :p
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Ignore the dent. Use it as a place to stick a half-eaten Power Bar. It's not worth repairing, and a TT doesn't get stressed all that much, so even though it may look gawd-awful, it's probably not going to fail anytime soon.
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I would find it irresistible, trying to fix that. Since it's aluminum, it probably will be weakened but the bends are gentle in nature. I'd try to fill the tube with water, seal it off and freeze. Repeat, if necessary, until it is fully expanded to normal. Might work. Little to lose.
Best, J |
Facial Reconstructive Surgery..........
Originally Posted by cb400bill
(Post 13250451)
Opinions? https://lh5.googleusercontent.com/-e...2/P1020419.JPG https://lh3.googleusercontent.com/-4...2/P1020418.JPG
Originally Posted by dddd
(Post 12057464)
The reason the frame cracked is because of the heat treating that was done to make the very thin tubing stronger (higher yield strength and higher fatigue strength), so it retains alignment and lasts longer during hard use.
However, heat-treated aluminum cannot be dented without introducing precurser cracks, and is thus no longer malleable. Any welding done after heat-treating will return the metal to it's original, weak state. If this frame doesn't use butted tubing, there is some excess of strength along the mid-sections of each tube, and the heat treating was done firstly to strengthen the ends, where the stresses are highest. Whether or not the middle of each tube is thick enough to retain sufficient strength after welding would be very hard to calculate however, and cracks anywhere in a heat-treated frame tend to spread rapidly in brittle (sometimes spectacular) fashion. I've seen and heard Cannondale frames snap in two, with a bang, the metal is that brittle! |
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I hope you have not stopped listening to suggestions. Look inside the seat tube and the head tube, think of a way to seal off one side and fill from the other with epoxy and microballoons. It will add weight but you won't have to worry about failure. Measure the size of the tube and fgure out the volume to see how much epoxy and microballoons you will need. Mix the microB to the maximum ratio with the least amount of epoxy. The end result is a little heavyer then foam but much stronger.
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Modeling clay and a sticker over the top of it.
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Rode a frame with a bend just almost exactly like that in that almost exact position for two years. It was a mountain bike however, and I road it almost completely offroad. Never had any problem with it whatsoever. Sold it to a co-worker who rides it still. I did give him a sweet deal on it because of the dent.
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it's not fixable, but it's probably ridable. I wouldn't freeze it, maybe use air and compression plugs. I also couldn't bring myself to sell it.
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Ride it the way it is, just as I do with perhaps the favorite rider in my collection, my Specialized Junker II. And though I do not do this, you can regale your friends and acquaintances with the how the crash damage occurred and you lived through it. Should be worth a beer or two at the pub with each telling. And each telling can embellish the last:-)
http://www.mytenspeeds.com/My_TenSpe..._Dent_TT_2.jpg |
Fill the top tube with expanding foam to give it support. Then fill the dent with all metal body filler, paint it and ride it like you stole it......
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I repaired a CAAD three with almost same dent.
I drilled a 1/4"hole on bottom of tube and used a brass rod and small hammer and tapped it for two hours and it all came out. Ed |
U can do that and then use acrylic paste to even it, sand it, prime it and paint it. Done.
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Originally Posted by cb400bill
(Post 13250451)
Tonight, when I arrived at the park for our weekly club ride, someone had left some bike parts with a handmade sign stating "FREE", leaning against a fence. In addition to the assorted tubes and tires, (which I also grabbed), was this Cannondale CAAD4 R3000 frame. I believe it to a model year 2000.
The issue with the frame appears to be a sizable dent in the top tube. It looks like something fell on it. Opinions? https://lh5.googleusercontent.com/-e...2/P1020419.JPG https://lh3.googleusercontent.com/-4...2/P1020418.JPG Brad |
People love the hammered look on fenders, so why not hammered frames? Hand me that baseball bat, please, and stand back.
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Originally Posted by tugrul
(Post 13250532)
Can you get an inner tube in there? Inflate it :p
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Originally Posted by afilado
(Post 13250684)
I would find it irresistible, trying to fix that. Since it's aluminum, it probably will be weakened but the bends are gentle in nature. I'd try to fill the tube with water, seal it off and freeze. Repeat, if necessary, until it is fully expanded to normal. Might work. Little to lose.
Best, J |
Originally Posted by bradtx
(Post 13251655)
Because of the dent there's little flip value. Ride it and pass it along to your grandkids.
Brad |
Bondo it, repaint it, and sell it.
Joking. |
Originally Posted by EddyR
(Post 13251602)
I repaired a CAAD three with almost same dent.
I drilled a 1/4"hole on bottom of tube and used a brass rod and small hammer and tapped it for two hours and it all came out. Ed Ed |
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