Cracked weld - serious ?

[[email protected]]

Finally got around to giving my latest bike a decent
cleaning, only to discover a crack in one of the welds.
It's where the top tube meets the seat tube, on the
underside. The bike's a '95 schwinn 'sidewinder' (cro-mo).

pic:
http://www.fractalfreak.com/wx/CrackedWeld.jpg

I got this bike used at a local bike shop a little less
than two years ago. I'm guessing the shop would
fix/warranty the frame, but I'm not certain. For all
I know it was already cracked when I purchased it.

It's annoying as I just went through the yearly routine
of replacing the chain/cluster & brake pads. I also got
a new back wheel. I'm rather poor and the bike's my
only source of transportation, so I really don't want
to give it up to have it fixed. I had been hauling a
lot of gear (20-30 pounds) on a back rack, which I've
since removed. I don't know if that would contribute to
the cracking.

Anyway, is this a cosmetic thing, or is it something
that must be fixed? It's not like it's in a really
high stress area, but I'd rather not have the seat
tube disintegrate while riding. Can I just keep an eye
on the crack and ditch the frame if it starts to
grow... or will failure be explosive?

Eric

 

[Werehatrack]

On 9 Apr 2006 04:15:30 -0700, [email protected] wrote:

>Finally got around to giving my latest bike a decent
>cleaning, only to discover a crack in one of the welds.
>It's where the top tube meets the seat tube, on the
>underside. The bike's a '95 schwinn 'sidewinder' (cro-mo).
>
>pic:
>http://www.fractalfreak.com/wx/CrackedWeld.jpg

The crack appears to be at the margin of the weld; IMLE, this is one
of the more common ways that welds in Cr-Mo tubing fail. You may be
able to forestall rapid propagation of the crack by stop-drilling it
at each end, and it may be possible to repair the frame by rewelding
(among other things). A good frame shop, and some specialty welding
shops that work with this type of material, could give you a better
idea of what's possible.

>I got this bike used at a local bike shop a little less
>than two years ago. I'm guessing the shop would
>fix/warranty the frame, but I'm not certain. For all
>I know it was already cracked when I purchased it.

It's possible, but hard to say. Given the location, the crack
certainly could have been overlooked.

>It's annoying as I just went through the yearly routine
>of replacing the chain/cluster & brake pads. I also got
>a new back wheel. I'm rather poor and the bike's my
>only source of transportation, so I really don't want
>to give it up to have it fixed. I had been hauling a
>lot of gear (20-30 pounds) on a back rack, which I've
>since removed. I don't know if that would contribute to
>the cracking.

I doubt that the rack had much to do with this.

>Anyway, is this a cosmetic thing, or is it something
>that must be fixed? It's not like it's in a really
>high stress area, but I'd rather not have the seat
>tube disintegrate while riding. Can I just keep an eye
>on the crack and ditch the frame if it starts to
>grow... or will failure be explosive?

If you're using this bike as a commuter and not for off-road trail
riding, you might get away with just riding it and keeping an eye on
the crack. Steel frames are much less likely to fail without warning
than those made from some other materials. I'd take it back to the
shop where you bought it, and see if they have anything to offer in
the way of help or advice. The Sidewinder's a common enough model
that you might be able to scrounge a used frame in decent shape and
just swap all the bits over. Failing that, the bike shop may have
some other comparable frame that would accept your existing running
gear without needing to do much more than build new cables and
possibly swap out the front der.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

 

[Mike Jacoubowsky]

> Anyway, is this a cosmetic thing, or is it something
> that must be fixed? It's not like it's in a really
> high stress area, but I'd rather not have the seat
> tube disintegrate while riding. Can I just keep an eye
> on the crack and ditch the frame if it starts to
> grow... or will failure be explosive?

It wasn't likely anything you did that caused the crack; more likely, a
crack in that area was caused by a prior user with the seatpost up too high.
This assumes you haven't had the seatpost up too high yourself, but it's not
clear from the photo. In any event, it's a serious, not trivial issue, as
continued use will eventually result in failure. How long is eventually?
Tough to say. But don't discount the forces placed in that specific area by
the seatpost. They were enough to create the failure in the first place, and
they'll continue as long as you ride the bike. If I was going to try and
keep it around as long as possible (without having it repaired), I'd use a
long, very rigid (not expensive & light) seatpost. And make sure it fits
*perfectly.*

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


<[email protected]> wrote in message
news:[email protected]...
> Finally got around to giving my latest bike a decent
> cleaning, only to discover a crack in one of the welds.
> It's where the top tube meets the seat tube, on the
> underside. The bike's a '95 schwinn 'sidewinder' (cro-mo).
>
> pic:
> http://www.fractalfreak.com/wx/CrackedWeld.jpg
>
> I got this bike used at a local bike shop a little less
> than two years ago. I'm guessing the shop would
> fix/warranty the frame, but I'm not certain. For all
> I know it was already cracked when I purchased it.
>
> It's annoying as I just went through the yearly routine
> of replacing the chain/cluster & brake pads. I also got
> a new back wheel. I'm rather poor and the bike's my
> only source of transportation, so I really don't want
> to give it up to have it fixed. I had been hauling a
> lot of gear (20-30 pounds) on a back rack, which I've
> since removed. I don't know if that would contribute to
> the cracking.
>
> Anyway, is this a cosmetic thing, or is it something
> that must be fixed? It's not like it's in a really
> high stress area, but I'd rather not have the seat
> tube disintegrate while riding. Can I just keep an eye
> on the crack and ditch the frame if it starts to
> grow... or will failure be explosive?
>
> Eric
>

 

[[email protected]]

Werehatrack wrote:

> The crack appears to be at the margin of the weld; IMLE, this is one
> of the more common ways that welds in Cr-Mo tubing fail. You may be
> able to forestall rapid propagation of the crack by stop-drilling it
> at each end, and it may be possible to repair the frame by rewelding
> (among other things). A good frame shop, and some specialty welding
> shops that work with this type of material, could give you a better
> idea of what's possible.
>

You're right in that the greatest length of the crack is in the top
tube right where it meets the weld. However if you look at the
pic you'll see there's another tendril attempting to cross the weld
to the seat tube.

I like the drill idea - it did occur to me. Heh, what with advances in
adhesives these days I even toyed with the idea of getting some
3M scotch-weld epoxy and slathering a little along the fracture.

> >I got this bike used at a local bike shop a little less
> >than two years ago. I'm guessing the shop would
> >fix/warranty the frame, but I'm not certain. For all
> >I know it was already cracked when I purchased it.
>
> It's possible, but hard to say. Given the location, the crack
> certainly could have been overlooked.
>

Like I say, I got the bike used and it had obviously been well
used and abused before I got it. The frame is loaded with
pits, scrapes, scratches and dents. Nearly all the welds were
covered in gunk until I cleaned the frame.

(...)

> If you're using this bike as a commuter and not for off-road trail
> riding, you might get away with just riding it and keeping an eye on
> the crack. Steel frames are much less likely to fail without warning
> than those made from some other materials. I'd take it back to the
> shop where you bought it, and see if they have anything to offer in
> the way of help or advice. The Sidewinder's a common enough model
> that you might be able to scrounge a used frame in decent shape and
> just swap all the bits over. Failing that, the bike shop may have
> some other comparable frame that would accept your existing running
> gear without needing to do much more than build new cables and
> possibly swap out the front der.

I ride primarily on the road. Both for fun, and commuting. So the
bike's important to me, it's not just a toy I take out on the weekend.
(i don't own a car)
I probably don't ride nearly as much as some of the bike dorks here
(~2.5-5 K/year) but it's my transportation... so it will be subject to
further fatigue. Anyway, it's not like it's an expensive bike, so I'll
be taking it back to the shop.

 

[[email protected]]

Mike Jacoubowsky wrote:

> It wasn't likely anything you did that caused the crack; more likely, a
> crack in that area was caused by a prior user with the seatpost up too high.
> This assumes you haven't had the seatpost up too high yourself, but it's not
> clear from the photo. In any event, it's a serious, not trivial issue, as
> continued use will eventually result in failure. How long is eventually?
> Tough to say. But don't discount the forces placed in that specific area by
> the seatpost. They were enough to create the failure in the first place, and
> they'll continue as long as you ride the bike. If I was going to try and
> keep it around as long as possible (without having it repaired), I'd use a
> long, very rigid (not expensive & light) seatpost. And make sure it fits
> *perfectly.*
>

No I don't think the seat post is too high. I've 4-5 " sticking out,
but there's another good 8-9" still in the frame. It a cheap heavy
seatpost that extends well past the problem weld - I just pulled
the seatpost to doublecheck this. I'm hoping the prior owner was
a fat-ass and caused the fault... but now that it's there it's not like
it's going to be getting any smaller

The shop I got the bike @ is huge... they may even have welding
facilities 'in-house'. They did replace a rear dropout that I broke on
another steel bike years ago (gratis), though that's something that's
easy to fix. The crack I'm seeing looks more like a frame destroyer,
especially considering how cheap the bike is.

Let you know how things turn out.

Eric

 

[Leo Lichtman]

<[email protected]> wrote: (clip) Heh, what with advances in adhesives
these days I even toyed with the idea of getting some 3M scotch-weld epoxy
and slathering a little along the fracture.
^^^^^^^^^^^^^^^^^^
Don't go beyond TOYING with the idea.

One thing you COULD do is rub a little paint into the crack, in a
contrasting color. Tyhen keep watching it, so see whether it grows beyond
the present size. If it's not growing, you can stop worrying. If it IS
growing, consider it dangerous. :-(

 

[Werehatrack]

On 9 Apr 2006 16:13:17 -0700, [email protected] wrote:

>Werehatrack wrote:
>
>> The crack appears to be at the margin of the weld; IMLE, this is one
>> of the more common ways that welds in Cr-Mo tubing fail. You may be
>> able to forestall rapid propagation of the crack by stop-drilling it
>> at each end, and it may be possible to repair the frame by rewelding
>> (among other things). A good frame shop, and some specialty welding
>> shops that work with this type of material, could give you a better
>> idea of what's possible.
>>
>
>You're right in that the greatest length of the crack is in the top
>tube right where it meets the weld. However if you look at the
>pic you'll see there's another tendril attempting to cross the weld
>to the seat tube.
>
>I like the drill idea - it did occur to me. Heh, what with advances in
>adhesives these days I even toyed with the idea of getting some
>3M scotch-weld epoxy and slathering a little along the fracture.

No adhesive is as strong as the tubing and the weld, and no adhesive
that's capable of wicking into the crack is strong enough to do
anything once it's there. The only thing that an adhesive will do in
this instance is make the eventual repair harder (if it's possible),
and conceal the crack's progress. Since it's essential that you be
able to see the crack spreading (if you decide to go that route, which
should be done only with considerable caution), covering it with an
adhesive sounds like a Really Bad Idea.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

 

[[email protected]]

Werehatrack wrote:
> On 9 Apr 2006 04:15:30 -0700, [email protected] wrote:
>
> >[...]a crack in one of the welds.
> >pic:
> >http://www.fractalfreak.com/wx/CrackedWeld.jpg

> Steel frames are much less likely to fail without warning

The frame is cracked. Maybe it's just me, but I think that constitutes
a warning. Is there some other warning you'd wait for?

 

[[email protected]]

Werehatrack wrote:
> On 9 Apr 2006 16:13:17 -0700, [email protected] wrote:
>

>
> No adhesive is as strong as the tubing and the weld, and no adhesive
> that's capable of wicking into the crack is strong enough to do
> anything once it's there. The only thing that an adhesive will do in
> this instance is make the eventual repair harder (if it's possible),
> and conceal the crack's progress. Since it's essential that you be
> able to see the crack spreading (if you decide to go that route, which
> should be done only with considerable caution), covering it with an
> adhesive sounds like a Really Bad Idea.
> --

Don't sweat it, I was joking. That's what the smiley face was for.

I will be keeping an eye on it, until and if I get it fixed.

Eric

 

[Michael Press]

In article
<[email protected]>,
[email protected] wrote:

> I ride primarily on the road. Both for fun, and commuting. So the
> bike's important to me, it's not just a toy I take out on the weekend.
> (i don't own a car)
> I probably don't ride nearly as much as some of the bike dorks here
> (~2.5-5 K/year) but it's my transportation... so it will be subject to
> further fatigue. Anyway, it's not like it's an expensive bike, so I'll
> be taking it back to the shop.

I am not inept at welding and brazing. On a low income I
would

1. Drill the three (!) ends of the cracks.
2. Scrounge equipment or shop time to fill the cracks with
brazing.

You will need to clean away the paint first, as the fumes
from burnt paint will poison the proposed weld.

--
Michael Press

 

[[email protected]]

Leo Lichtman wrote:

> One thing you COULD do is rub a little paint into the crack, in a
> contrasting color. Tyhen keep watching it, so see whether it grows beyond
> the present size. If it's not growing, you can stop worrying. If it IS
> growing, consider it dangerous. :-(

Prolly what I'll do for the time being.

Of course if something fails down there while I'm descending and I
end up with a severly impacted rectum I'll have no one to blame
but myself.

Eric

 

[Werehatrack]

On 9 Apr 2006 17:56:07 -0700, [email protected] wrote:

>Werehatrack wrote:
>> On 9 Apr 2006 04:15:30 -0700, [email protected] wrote:
>>
>> >[...]a crack in one of the welds.
>> >pic:
>> >http://www.fractalfreak.com/wx/CrackedWeld.jpg
>
>> Steel frames are much less likely to fail without warning
>
>The frame is cracked. Maybe it's just me, but I think that constitutes
>a warning. Is there some other warning you'd wait for?

There's failure and thenthere's failure. Yes, there's a crack; a
technical fault which has not yet caused the bike to become
inoperable. It may or may not proceed to an operational failure which
takes the unit out of service...and which might do the same to the
rider if it took place at the wrong time. If this was an aluminum or
carbon frame, I'd say that it should be carried to the shop; both of
those are given to progressing from fault to failure rapidly. With
steel, the rate of failure propagation is likely to be slow; the
chances are good that the crack has been present for days or months at
least, and has not become dramatically worse in that period. I would
have no qualms about riding it to the shop...but I wouldn't take it
touring, and I wouldn't recommend any long dailies either. It's the
kind of thing that needs to be watched closely if the unit can't be
immediately replaced IMO, but I don't think it's necessary to panic.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

 

[RonSonic]

On 9 Apr 2006 19:13:35 -0700, [email protected] wrote:

>
>Leo Lichtman wrote:
>
>> One thing you COULD do is rub a little paint into the crack, in a
>> contrasting color. Tyhen keep watching it, so see whether it grows beyond
>> the present size. If it's not growing, you can stop worrying. If it IS
>> growing, consider it dangerous. :-(
>
>Prolly what I'll do for the time being.
>
>Of course if something fails down there while I'm descending and I
>end up with a severly impacted rectum I'll have no one to blame
>but myself.


"Rectum!? Did more'n rectum, durn near kilt 'im!

Ron

 

[A Muzi]

> On 9 Apr 2006 04:15:30 -0700, [email protected] wrote:
>>Finally got around to giving my latest bike a decent
>>cleaning, only to discover a crack in one of the welds.
>>It's where the top tube meets the seat tube, on the
>>underside. The bike's a '95 schwinn 'sidewinder' (cro-mo).
>>pic:
>>http://www.fractalfreak.com/wx/CrackedWeld.jpg

Werehatrack wrote:
> The crack appears to be at the margin of the weld; IMLE, this is one
> of the more common ways that welds in Cr-Mo tubing fail. You may be
> able to forestall rapid propagation of the crack by stop-drilling it
> at each end, and it may be possible to repair the frame by rewelding
> (among other things). A good frame shop, and some specialty welding
> shops that work with this type of material, could give you a better
> idea of what's possible.

-snip-

I saw this very bike today.

Given the location and depth of the crack, I advised him to
paint it, ride it and watch for further cracking.

If a crack opens in the middle of a tube, as a handlebar
bash in a top tube, yes drilling the ends of the crack then
filling with silver can be a good way to stop the crack from
growing. I doubt anything can be gained here.

IMHO we're looking at a bad weld that's been just like this
from Day One and not a crack which appeared yesterday.

Moreover since the seat post is inserted well beyond the
crack and a failure here won't hurt the rider, leaving it
alone is the best path. I advised him that should it open
further we can reweld the joint later.

That would open an interesting course of inquiry. If it were
not a poor pass but rather had openend after some miles and
continued to grow, the proper repair is to open the joint
and then reweld to relieve internal stress. Cracks in frame
joints almost always begin with a frame forced to shape and
brazed/welded under tension.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[[email protected]]

A Muzi wrote:

>
> I saw this very bike today.
>
> Given the location and depth of the crack, I advised him to
> paint it, ride it and watch for further cracking.
>
(snip)

Thanks for the advice.

I took the bike to Budget (where I'd originally purchased it) and
they sanded the paint off the weld. It didn't look as intimidating
that way. Budget told me it likely wasn't serious, and there
wasn't much they could do about it anyway. Decided I wanted a
second opinion and took the bike to YellowJersey where Mr.
Muzi told me the same thing.

So I'll keep an eye on it and keep riding.

Eric

 

[Király]

[email protected] wrote:
> Finally got around to giving my latest bike a decent
> cleaning, only to discover a crack in one of the welds.
>
> It's annoying as I just went through the yearly routine
> of replacing the chain/cluster & brake pads.

That's always the way it goes! I finished a major maintenance to my
bike; thorough cleaning, new cup & cone bottom bracket, new headset, all
new cables and housing, etc. Spent a whole afternoon. Just when I was
tightening up the last bolt I noticed that the seat tube had completely
separated from the bottom bracket shell. D'OH! So that's why the bike
had felt a little "flexy" lately. To the junk pile it went.

K.

 

[John Thompson]

On 2006-04-14, Király <[email protected]> wrote:

> That's always the way it goes! I finished a major maintenance to my
> bike; thorough cleaning, new cup & cone bottom bracket, new headset, all
> new cables and housing, etc. Spent a whole afternoon. Just when I was
> tightening up the last bolt I noticed that the seat tube had completely
> separated from the bottom bracket shell. D'OH! So that's why the bike
> had felt a little "flexy" lately. To the junk pile it went.

That's how I got my current commuter bike, an early 70s vintage Italian
club racer frame. Previous owner noticed BB shell was cracked all the way
around the seat tube insertion. Owner was going to junk it, but gave it
to me instead. I sweated off the old BB shell and brazed in a new one.
That was about 20 years ago now, and I'm still riding it almost every day.

--

John ([email protected])