Steel frame damage ...
 

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[Closed] Steel frame damage - always visible?

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I've a frame which has a head angle out by a couple of degrees from what it's supposed to be. I can't see any obvious damage like cracks around the head tube or seattube junctions. Is it possible for a frame to deform with no outward signs? Its a brazed frame which might make a difference? Builder is adamant that it was correct when first built, and I've no reason to disbelieve them.
Edit - To avoid some questions, It's a BMX frame so fork lengths are standard, and head angles from the builder are fixed at 74.5 degrees. This frame measures 76.5 degrees.


 
Posted : 02/10/2017 1:01 pm
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Enough to be out by that much I'd have thought so? Do you know the frame's, history, maybe the headtube came off and has been brazed back on?

When tube's crumple under axial compression they tend to go completely, they don't have much plastic deformation.


 
Posted : 02/10/2017 1:25 pm
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Do you know the frame's, history

I've owned it since new.


 
Posted : 02/10/2017 1:26 pm
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It's a BMX frame so fork lengths are standard

Standard [i]within a range[/i], there is still variation between manufacturers and models, is it the original fork from the builder fitted? Likewise headset stack height (if external) can vary by a few mm too.

This frame measures 76.5 degrees.

Absolutely sure your measurements are correct?

There'd normally be some apparent deformation for a change of that magnitude, you might need to look quite closely but you should be able to see or [i]feel [/i]something, rippling/bulging of a tube, a crease, etc.


 
Posted : 02/10/2017 1:37 pm
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is it the original fork from the builder fitted?
Nope, but it's a standard length BMX fork and AFAIK they don't differ that much.
Absolutely sure your measurements are correct?
Pretty sure, measured mine, facing both ways then another bike in the same location which came out as expected at 74.5. Also you could visibly see it was steeper just by eyeballing it.
There'd normally be some apparent deformation for a change of that magnitude, you might need to look quite closely but you should be able to see or feel something, rippling/bulging of a tube, a crease, etc.
Is what I thought. Maybe I need to take another closer look but I even removed some paint to check last time and still could see nothing.


 
Posted : 02/10/2017 2:29 pm

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