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Discussion Starter · #1 ·
Hi,

I have a KHS Flite 800 frame (Reynolds 853) which I crashed while racing last Sunday. The frame acquired a dent on the non-drive side chainstay, about half way along its length (pictures below). The dent is not too large, about 1mm deep at its worst, and involves about one quarter the diameter of the stay. The dent does not contain a crease in the metal, it's a pretty smooth indentation. The paint is unmarked, except for a very small split at the very bottom of the dent. The stay (which should be straight) was also knocked inwards about 1mm off straight, with the worst of the deviation centred at the dent.

I've checked the spaced of the rear dropouts, and it is unaffected by the bent chainstay (still 130mm). I dropped a wheel into the dropouts and tightened it up. A visual check seems to show that it is just about equidistant from both chainstays.

So, here are my questions:

1) With this being a steel frame, a dent like this, in this location, probably shouldn't be a major issue. Is this correct?

2) Would such a small deviation in the chainstay have any serious reprecussions on the handling of the frame? The frame should obviously be checked for alignment, I know, but if the chainstay wasn't straightened is a 1mm deviation going to throw tracking all to heck, or would this be in the ballpark for normal frame misalignments?

I really like this frame, and I want to be able to keep racing on it, but of course I want to have confidence in it also. Any advice or personal experiences would be gratefully received!
 

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I would ask KHS for an opinion and I would also ask them what it would take to repair that. After all it is steel and the right frame builder could easily repair that.

Just from the photos however, it looks like you should have no issues riding the bike. But personally I would try to fix it.
 

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Take all the paint off the area of the dent.

You gotta find out what is going on under the paint.

Look carefully for cracks. If there are none respray the area with flat black and keep your eye out for cracks developing (steel is very tough so it is unlikely to suddenly fail).

If it isn't cracked I would have no issues riding that frame.
 

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How do you reach your conclusion?

serious said:
I would ask KHS for an opinion and I would also ask them what it would take to repair that. After all it is steel and the right frame builder could easily repair that.

Just from the photos however, it looks like you should have no issues riding the bike. But personally I would try to fix it.
I'm not a mechanical engineer, but when I see a crease like that in a dent I suspect that the strength of the seat stay has been seriously compromised. Just from the photos, I wouldn't ride it.

serious, how did you decide that that there should be no issues riding theh bike?
 

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Discussion Starter · #5 ·
Reynolds531 said:
I'm not a mechanical engineer, but when I see a crease like that in a dent I suspect that the strength of the seat stay has been seriously compromised. Just from the photos, I wouldn't ride it.

serious, how did you decide that that there should be no issues riding theh bike?
It's not in the seat stay, it's in the chain stay. The chain stay is considerable thicker in diameter, which should decrease the effect of a small dent on the overall integrity of the structure, I would think. The metal in the centre of the dent is not creased, the curve is smooth, which may reduce the chances of a destructive stress riser which could cause the stay to fail. I'm really looking for insights from people who have had a similar problem in a steel frame, to see how they fared with it.
 

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Discussion Starter · #6 ·
MB1 said:
You gotta find out what is going on under the paint.

Look carefully for cracks. If there are none respray the area with flat black and keep your eye out for cracks developing (steel is very tough so it is unlikely to suddenly fail).

If it isn't cracked I would have no issues riding that frame.
Thanks, that sounds like good advice!

:)
 

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If the dent is in the middle (half wayish between the ends) I'll bet you can ride it for the rest of your life without issue. If on the very rare chance it does break it will do so very slowly and not leave you walking

Repair it if the look bothers you.

Dave
 

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David Kirk said:
If the dent is in the middle (half wayish between the ends) I'll bet you can ride it for the rest of your life without issue. If on the very rare chance it does break it will do so very slowly and not leave you walking

Repair it if the look bothers you.

Dave
It's quite possible that Dave would win his bet, but 853 is generally very thin-walled stuff, so I'm not 100% sure. I would definitely look under the paint. Also, a good metal worker might be able to roll that dent mostly out of that tube. I don't know much about such operations, but I hear they can be done.

Good luck!

- FBB
 
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