Crack on seat lug (top) of 1987 ALAN; slow failure or catastrophic failure?
07-17-19, 03:34 PM
#51
Full Member
Hello there!
A crack has developed along the top of the seat post lug of my 1987 ALAN. (When I bought the bike second hand in 2010, the crack was one third of what it is now, stemming from the seat post. Over time, it developed into what you can see here.)
I have accepted that this means the failure of the frame, or else hanging it on the wall (god damn, it's beautiful!). Yes, I know that these frames can't be welded; and yes, I have a steel-framed bike. But I was wondering if I could wrap a hose clamp around this lug, and use the frame for gentle rides, until failure occurred.
However, I could only do this if the failure was slow and safe (e.g. the top tube started to rattle), and not if the failure was to be sudden and violent (e.g. the top tube suddenly separated from the lug, half of the bike lurched forward, and I fell into the front wheel and the road).
So, does anyone have the experience and/or engineering know-how to answer? What would it be -- slow or sudden failure?? Help would be greatly appreciated!!
^ The crack up close.
^ The crack from further back.
^Assorted hose clamps--up to the task?
A crack has developed along the top of the seat post lug of my 1987 ALAN. (When I bought the bike second hand in 2010, the crack was one third of what it is now, stemming from the seat post. Over time, it developed into what you can see here.)
I have accepted that this means the failure of the frame, or else hanging it on the wall (god damn, it's beautiful!). Yes, I know that these frames can't be welded; and yes, I have a steel-framed bike. But I was wondering if I could wrap a hose clamp around this lug, and use the frame for gentle rides, until failure occurred.
However, I could only do this if the failure was slow and safe (e.g. the top tube started to rattle), and not if the failure was to be sudden and violent (e.g. the top tube suddenly separated from the lug, half of the bike lurched forward, and I fell into the front wheel and the road).
So, does anyone have the experience and/or engineering know-how to answer? What would it be -- slow or sudden failure?? Help would be greatly appreciated!!
^ The crack up close.
^ The crack from further back.
^Assorted hose clamps--up to the task?
Let me underscore that that bike is NOW a deathtrap and can have catastrophic failures at any time. You do not want to be riding down a hill or going fast with a strong tailwind and have the rear triangle fall off.
07-22-19, 01:35 AM
#52
Full Member
I'll unsubscribe from this subject overloaded with answers not reading Skiron posts.
It drifted away and transformed into a don't like Alan, don't like Vitus storm...
It drifted away and transformed into a don't like Alan, don't like Vitus storm...
Likes For Munny:
07-22-19, 05:36 AM
#53
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-Kurt
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07-22-19, 06:21 AM
#54
Full Member
How painfull it is to be quoted after you express the desire NOT to hear about this.
How difficult is it to READ what have been the exchanges and to consider the other answers confusing ... Vitus and Alan, a vintage bike (Alan) with non vintage US bikes difficult to obtain in the country of the poster, etc etc...
Kurt, If you had read the author, he had already purchased a replacement and he was only looking to see if TEMPORARELY he could ... until the new frame came
I would NOT do it with my Alan but I have seen worse fracture at the same place being riden for a long time. I rode alongside one of them for 100 Km,..
I've seen other being repaired
This was not the question.
If you want to continue a bunch of post here, I'm not interested
How difficult is it to READ what have been the exchanges and to consider the other answers confusing ... Vitus and Alan, a vintage bike (Alan) with non vintage US bikes difficult to obtain in the country of the poster, etc etc...
Kurt, If you had read the author, he had already purchased a replacement and he was only looking to see if TEMPORARELY he could ... until the new frame came
I would NOT do it with my Alan but I have seen worse fracture at the same place being riden for a long time. I rode alongside one of them for 100 Km,..
I've seen other being repaired
This was not the question.
If you want to continue a bunch of post here, I'm not interested
07-22-19, 08:28 AM
#55
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How painfull it is to be quoted after you express the desire NOT to hear about this.
I've removed your user ID in the quotation code, so hopefully it won't notify you again. I would think the forum must have some system to turn this off at your end though.
Kurt, If you had read the author, he had already purchased a replacement and he was only looking to see if TEMPORARELY he could ... until the new frame came
I would NOT do it with my Alan but I have seen worse fracture at the same place being riden for a long time. I rode alongside one of them for 100 Km,..
Discussion about the structural integrity of ALAN frames is pretty much required to assess the OP's frame failure, so yes, this is relevant to the discussion - because it is an inherent part of the answer.
If you want to continue a bunch of post here, I'm not interested
-Kurt
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07-29-19, 02:42 AM
#56
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Hi Kurt; no, I wasn't fishing for community agreement. I was looking for specific information about how this lug would fail, based on experience or mechanical know-how. In large part, this was down to curiosity about how frames are held together. The post above, about frame tension, was just the kind of thing I was looking for, as were the anecdotes about riding alongside ALANs/Vituses with this kind of failure.
All the best
All the best
07-29-19, 05:49 AM
#57
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Hi Kurt; no, I wasn't fishing for community agreement. I was looking for specific information about how this lug would fail, based on experience or mechanical know-how. In large part, this was down to curiosity about how frames are held together. The post above, about frame tension, was just the kind of thing I was looking for, as were the anecdotes about riding alongside ALANs/Vituses with this kind of failure.
All the best
All the best
I do think frame tension can't be simplified as explained here though, depending on the forces being applied to the frame at any one given moment - especially during braking.
-Kurt
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