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Old 06-30-05, 02:58 PM   #1
FisherKid
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Is a dented frame the end of a bike??


These dents are on the top tube. The frame is aluminum (Easton) The bike is for sale, but if the dents make it unsafe, I won't do it. Thanks in advance

Cory
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Old 06-30-05, 03:32 PM   #2
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Top tube dents are less dangerous than downtube...IMO?
If chromoly...I might personally ride.
Alu.....no, and those are around the tube -not in one spot so the tube integrity is most likely compromised.
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Old 06-30-05, 04:25 PM   #3
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Yeah, kinda iffy...
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Old 06-30-05, 04:53 PM   #4
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I (don't have the frame rigidity test numbers to demonstrate my position) but I would stay away from such a very visibly dented frame.
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Old 06-30-05, 05:09 PM   #5
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if those three dents were consolidated into 1 dent I would say maybe....but with 3 of them which appear to be quite deep I say no.
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Old 06-30-05, 05:10 PM   #6
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I say maybe....hammer to it...check it out...Pop them out like on a car. But if it is not straight and effects riding. NO
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Old 06-30-05, 06:21 PM   #7
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Hmmm??

If it's going to get painted, it seems to me, there are options. The dents could be filled with some good quality structural epoxy, which I'd guess would be stronger than the original. The area could have a "saddle" placed over the affected area. This might be a split tube that could be cemented over the dented tube. Or, the top tube could be replaced. ??
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Old 06-30-05, 06:27 PM   #8
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Hmmm??

If it's going to get painted, it seems to me, there are options. The dents could be filled with some good quality structural epoxy, which I'd guess would be stronger than the original. The area could have a "saddle" placed over the affected area. This might be a split tube that could be cemented over the dented tube. Or, the top tube could be replaced. ??
I'd say no to your first point, only the dent cavity will be stronger, not the tube as a cylinder.
Point 2...ya, I'd cut lengthwise and long, put the 2 halves on and mechanically
clamp them..maybe something like hose clamps. http://www.plumbingsupply.com/clamps.html
Or beefier. Several. Fugly but may work.

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Old 06-30-05, 07:13 PM   #9
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Try this. Take a piece of paper, roll it up in a tube, pull on it. Doesn't give much right?
Put a dent in it, pull on it, doesn't give much right?
Take a new piece of paper, roll it up in a tube, push down on it, doesn't give much right?
Now put a dent in it, push down on it, WHAM, it buckles.

Now in a triangle, the top tube is under compression.
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Old 06-30-05, 09:19 PM   #10
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Don't buy into other people's problems.
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Old 06-30-05, 09:31 PM   #11
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I wouldn't buy a dented bike period. What supcom said.
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Old 07-01-05, 12:22 AM   #12
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I posted pretty much an identical question several days ago:

Dented tubes
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Old 07-01-05, 03:53 AM   #13
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Quote:
Originally Posted by wasabiboys
I say maybe....hammer to it...check it out...Pop them out like on a car. But if it is not straight and effects riding. NO

No. Aluminum is suited for bending back. The aluminum is already thinning substantially and bending it back will thin the metal on the opposite from that which has allready been thinned.

If this is a lugged frame, might be possible to replace the top tube.

If not, sleeving the damaged section might be another option, but that entails a mild weight penalty.
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Old 07-01-05, 05:07 AM   #14
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No. Aluminum is suited for bending back. The aluminum is already thinning substantially and bending it back will thin the metal on the opposite from that which has allready been thinned.

If this is a lugged frame, might be possible to replace the top tube.

If not, sleeving the damaged section might be another option, but that entails a mild weight penalty.
Tig welded chromoly it is possible to replace tubes as well.

I'd do it for my chromoly frame bike...I bought it WITH a dent in the toptube.

I've yet to do worse as far as damage.
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Old 07-01-05, 10:16 AM   #15
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Irrelevant information since the frame is AL.
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Old 07-01-05, 10:25 AM   #16
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I'd ride it, but I wouldn't let my daughter ride it.
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Old 07-01-05, 10:58 AM   #17
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I'd let someone else ride it.
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Old 07-01-05, 11:12 AM   #18
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I have a '83ish Trek with a Reynolds 531 frame. It has a dent on the top tube that is three or four inches long, and about half an inch high. At its deepest point, it is a quarter inch deep. When you look directly down at the top tube, it looks as if it has a "waist" at the dented section. The size and shape of the dent make it look as if someone banged the bike hard against a wide pole. Real hard.

The bike rides fine. The dent has no significance at all, beyong making a rusty old bike with an ugly green DIY paint job look a bit uglier. Reynolds 531 has thicker walls than 2005 aluminum frames. And, steel behaves differently under bending stress than aluminum. I doubt I would feel as comfortable if MY dent was on a aluminum frame, rather than a 531 frame.
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Old 07-01-05, 01:30 PM   #19
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It probably won't compromise the day to day rigidity of the frame much but it will make the frame tube buckle at a much lower load than it would normally. So in a crash it will tend to fold right where you've got that dent.

Also heat treated aluminum doesn't take so well to cold setting so you can't pop the dent out like you would with steel. Once aluminum has been yielded the fatigue life is reduced substantially.
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Old 07-01-05, 04:00 PM   #20
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Price the bike for its used components and replace the frame. That's what framesets are sold for. Can always get an inexpensive frame of perfect fit or close to your required size, maybe last year's model, hanging on the wall in almost every bike shop.

Unlesss there's some special value attached to the frame - like this was the bike Lance or Merckx used for their first tour wins (In that case buy the bike and put it back on the wall)
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Old 07-01-05, 05:08 PM   #21
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If you cant bent it back...I would not waste time on new headtube!
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