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-   -   Frame repair - straightening question (http://www.bikeforums.net/general-cycling-discussion/229058-frame-repair-straightening-question.html)

chicbicyclist 09-17-06 12:46 AM

Frame repair - straightening question
 
So this he Sedan hit me while I was crossing a fourway stop intersection. It was clearly my turn, the guy in front of him went ahead and it was my turn to go. He hit me dead on the right side, landed on his hood and made quite an impression. I was fine, got a very minor roadrash on my right elbow and a huge bruise thats healing pretty nicely on my left knee.

As for my question, I want to know more general infos about straightening a chromoly steel frame. I would get a new bike, but I want to do as much as I can to keep this one because most bikes with this geometry now comes in Aluminum. I hate aluminum.

Anyway, there was no visible bending to my bike at all. I can't even tell if its bent or not, but my mechanic says I should get a new one. Even the headtube looks fine. I find it odd since I can't find any cracks on the tube itself or on the welded parts, some aesthetic scratches yeah. And it is chromoly steel after all. Steel is supposed to be more flexible than aluminum. Why is he insisting on replacing the whole thing? It's odd, since many more fragile roadbikes involved in worst crashes can be fixed. Is it adviseable to get a second opinion? whats the general cost of straightening a frame? Can it only be done on the dropouts and not on the maintube itself?

What exactly should I look for in the frames to determine wether or not it is still fixable? And while we're at it, how do I become a paying subscriber to bikeforums?

operator 09-17-06 08:45 AM

You got hit by a car but there's no damage to the frame at all? Is it a lugged steel frame? If something is slightly misaligned you can get it coldsetted back but if there are kinks or bends in the tubes then it's game over.

You can keep riding your frame, but i'd seriously inspect EVERYTHING over with a microscope to look for cracks in the paint/damage to any part of the bike frame itself. Pay attention to the noises your bike makes as well. A crack may manifest itself as a creaking noise.

ericgu 09-17-06 07:12 PM

Steel is better at deforming without breaking than other materials, *but* there is a limit of both the steel tubes and the connections between the tubes. You can get damage that isn't really visible but would reduce the speed in the future.

Your mechanic wants to replace it for one (or both) of the following:

1) He can bill some good time in moving the old parts to the new frame.
2) He's on the hook for saying, "the frame is okay" if you get into problems in the future.

If I was a mechanic, I would do exactly what your mechanic is doing because of #2.

There are inspections that can be done to tell for sure - such as X-rays - but they may not be cost-effective in this case.

slowandsteady 09-18-06 09:37 AM

If you get an insurance check, there is nothing saying that you have to get an aluminum bike. Just go out and buy the cromoly frame that you want(used I assume) and build it up to your specs with the rest of the money.


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